Arc 15The Ring Research Institute

Qin Yiguan gathered the materials needed to replace the Ring Research Institute, defeated Bo You’s plans through Timeline Convergence, and took control of the new institute. A flashback then revealed that clones of his adoptive parents had drowned his mother, and Qin began investigating what happened to her body.

  • Bo You ordered Lu Guang to kill Guan Liujue and Song Miao, while Jiang Yizhou hid the meteorites and Song Miao told Qin Yiguan she would betray the institute and die seven days later.
  • Song Miao’s recording explained that the Ring Research Institute was a time-traveling structure dependent on rare materials, and Qin Yiguan learned she had been taken from the river of time.
  • Qin Yiguan saved Dr. House from Lu Guang, learned Song Miao had been defiled, and promised House she would return.
  • Bo You sent Lu Guang back to his younger self, but the younger Lu Guang revealed that Qin Yiguan had already killed him, and Lu Guang faded from the timeline.
  • Qin Yiguan and his allies collected the institute’s materials across time, including the final pieces from a sound-based parallel universe, while Bo You’s institute deteriorated and Bo You’s health failed.
  • Bo You revealed that the institute had cloned Qin Yiguan and ordered Shitian to kill him, but Qin used Timeline Convergence to defeat the attack and free Jiang Yizhou from Bo You’s control.
  • Qin Yiguan replaced Bo You’s institute with one he had built in 2122, where the researchers joined his side, and Song Miao helped expose and kill Bo You.
  • Qin Yiguan fused with the Boundless One, set the Digital Humans and Shitian on their paths, then revisited his mother’s death and saw Bo You’s clones drown her before one buried her body.
Chapters 351–375 Vol. 4 Read

Ch. 351Time's Traitor

Jiang Yizhou hid the meteorites in Zhao Kuangyin’s palace in the Song Dynasty while the Ring Research Institute searched for them. Qin Yiguan then met Song Miao, who revealed she would betray the Institute and be killed seven days later in this era.

  • Bo You ordered Lu Guang to kill Guan Liujue and throw his body into the sinkhole after Guan promised to search for meteorites.
  • Bo You had Lu Guang kill Song Miao, believing she would betray the Ring Research Institute later that day, though it was only eight in the morning.
  • The Ring Research Institute launched unmanned aircraft to search the continent for the meteorite, while Bo You suspected someone had hidden it elsewhere.
  • Jiang Yizhou told Qin Yiguan he planned to hide the meteorites in Zhao Kuangyin’s imperial palace, and Liu Quan C and Liu Shuan Q transported them with the mechanical spider.
  • Jiang Yizhou sensed someone with a time-related ability approaching, and Song Miao arrived beside Qin Yiguan.
  • Song Miao told Qin Yiguan she belonged to the Ring Research Institute, would betray it seven days later in this ancient era, and could never see House again.

Ch. 352An Old Friend in Time

Song Miao explained that the Ring Research Institute was a time-traveling vessel that needed rare materials and replacement personnel, and she entrusted Qin Yiguan with information to help destroy it. She disappeared after confirming she had truly died, leaving Qin Yiguan to study her files and investigate the institute’s missing senior staff.

  • Song Miao told Qin Yiguan that her planned death seven days later was meant to make the Ring Research Institute lower its guard, and entrusted him with a projection device.
  • Song Miao explained that House’s words about genuine kindness had helped her recognize the Ring Research Institute’s true nature, then confirmed she had actually died and vanished.
  • Qin Yiguan played Song Miao’s recording, which described the Ring Research Institute as a Ship of Theseus traveling through time and explained that it needed rare materials to repair its structure.
  • Song Miao revealed that removing the meteorite would delay the institute’s repairs, but Qin Yiguan would need to remove many more materials to destroy it.
  • The projection displayed a detailed inventory of the institute’s materials and personnel, including employees from different historical periods and several missing senior staff; Qin Yiguan asked how personnel could be repaired.

Ch. 353Causal Cycle

Qin Yiguan discovered that Song Miao had joined the Ring Research Institute in 2119, and suspected it had taken her from the river of time. When he tried to contact Dr. House, he found no record of him and set out on an urgent journey.

  • Lu Guang told Bo You that Song Miao had died and that the institute needed someone to fill her position.
  • In 2119, Bo You recruited Song Miao into the Ring Research Institute as its time coordinate administrator.
  • Lu Guang warned Bo You that House could become a powerful threat, and Bo You ordered him to kill House.
  • Lu Guang lured House into turning away, then broke his neck.
  • Qin Yiguan found Song Miao on the institute's personnel list and suspected the institute had taken her from the river of time.
  • Qin Yiguan failed to find Dr. House through the communicator, left the meteorite with Teacher Jiang and Shitian, and set out to travel 3,000 kilometers.

Ch. 354Time's Lackey

Qin Yiguan intervened as Lu Guang tried to kill House and learned that Lu Guang was tied to Song Miao’s disappearance. After Qin Yiguan mortally wounded Lu Guang, a beam of blue light whisked him away, leaving Qin Yiguan searching the empty distance.

  • Qin Yiguan appeared behind Lu Guang, broke both his arms, and tore them off while saving House.
  • Qin Yiguan recognized Lu Guang’s Ring Research Society badge and accused him of being connected to Song Miao’s disappearance.
  • Lu Guang transformed, charged Qin Yiguan, and claimed he would take credit for killing him.
  • Starvation Corpse identified Lu Guang as a delicacy, and Qin Yiguan transformed and tore open Lu Guang’s chest, cutting his heart into four pieces.
  • Qin Yiguan kicked Lu Guang away, but a beam of blue light enveloped Lu Guang and made him disappear before Qin Yiguan could finish him.

Ch. 355This Is the Truth

Qin Yiguan resisted Dr. House’s hypnosis and used his own ability to hypnotize Dr. House, who was desperately seeking news of Song Miao. Qin Yiguan reassured him that Song Miao would return, then asked him to be patient with a future young man surnamed Qin.

  • Dr. House tried to hypnotize Qin Yiguan and demanded to know who he was, what had happened, and where Song Miao was.
  • Dr. House manifested a partial Higher Self, but Qin Yiguan’s complete Higher Self, Plunderer, nullified the hypnosis and copied Dr. House’s ability.
  • Under Qin Yiguan’s hypnosis, Dr. House revealed that Song Miao had been defiled, and Qin Yiguan suppressed his anger.
  • Qin Yiguan told Dr. House that Song Miao had been drawn into time, had not forgotten him, and would return.
  • Qin Yiguan asked Dr. House to be patient with a future young man surnamed Qin, who would grow into a powerful person, and Dr. House agreed.

Ch. 356Employee Recruitment

Bo You learned that a silver-skinned Qin Yiguan had nearly killed Lu Guang, then recalled how he had recruited Lu Guang by arranging for his father to clone and imprison his sons. The chapter left Bo You facing an unknown timeline as a gap began forming in the Ring Research Institute’s closed-loop emblem.

  • Lu Guang returned to the Ring Research Institute gravely wounded and said Qin Yiguan had attacked him as a silver-skinned being with fangs and horns.
  • Bo You doubted Lu Guang’s account because he knew Qin Yiguan had no abilities or time-related powers.
  • Bo You recalled visiting a Metaverse official forty-two years earlier and offering cloning technology and a plan to raise descendants in darkness in exchange for the fifth son.
  • Bo You returned twenty-one years later, found the fifth son in a dark chamber, and renamed Wu Zheng Xuan as Lu Guang.
  • Bo You saw that part of the Ring Research Institute’s closed-loop emblem was growing faint while Lu Guang begged him for help.

Ch. 357Resurrection

Lu Guang survived his injuries with the Ring Research Institute’s technology and planned to return to his younger body, while Qin Yiguan enlisted Jiang Yizhou and Shitian to collect materials needed to dismantle the institute. The chapter ended with Qin Yiguan deciding to kill Lu Guang.

  • Bo You gave Lu Guang a consciousness enhancement shot and ordered him to travel back twenty-one years and inject his past self with his memories.
  • Lu Guang left to return to his younger body and vowed to take revenge on Qin Yiguan and his family.
  • In the Song Dynasty palace’s underground icehouse, Jiang Yizhou, Shitian, and Qin Yiguan discussed the stored meteorites and tried Bashu tribute peppers.
  • Qin Yiguan asked Jiang Yizhou and Shitian to retrieve more than thirty Ring Research Institute repair materials from different points in time and bring them to the icehouse.
  • Qin Yiguan identified Lu Guang on the institute’s employee roster and said he was going to kill him.

Ch. 358Former Body

Lu Guang returned to the Black Room to take over his former body, only to find that his twenty-one-year-old self had died and Qin Yiguan was waiting for him. As Lu Guang faded from the timeline and succumbed to his wounds, Qin Yiguan began torturing him with the little demons created by Gestalt Collapse.

  • Lu Guang traveled back through the Ring Research Institute to the Black Room, where he expected to replace his former self.
  • Lu Guang opened the fifth door and found his twenty-one-year-old corpse hanging from the ceiling while his former self sat watching him.
  • The youth explained that Lu Guang had returned to take over a new body, but that his former self had already been killed by Qin Yiguan.
  • Lu Guang's wounds worsened as the consciousness-enhancing injection wore off, and he collapsed in the doorway.
  • The youth used Gestalt Collapse to send little demons after Lu Guang, who could no longer fight back.
  • Lu Guang began disappearing from his feet upward, and the youth realized he was both fading from the timeline and dying from his injuries.

Ch. 359The Door to History

Qin Yiguan discovered the identities behind the Lu Zun incident and traveled twenty-one years into the past, where he confronted a young Lu Zun and found a child Jiu Zhengxuan. Meanwhile, Lu Guang’s remains vanished at the Ring Research Institute as Bo You learned that much of the institute’s outer shell had deteriorated.

  • Qin Yiguan realized that Zhong Yi was behind the Lu Zun incident, that Lu Zun was Liu Zheng Xuan, and that the dead Lu Guang was Wu Zheng Xuan.
  • Qin Yiguan recognized the young Liu Zheng Xuan as Lu Zun, knocked away his beam pistol, and shattered his right leg before leaving him alive.
  • Qin Yiguan opened the ninth Black Room and found a child Jiu Zhengxuan, whom he called the light of his life before shutting the door.
  • Bo You watched Lu Guang’s returned remains dissipate into time and struck a table in anger.
  • A researcher told Bo You that over twenty-two percent of the Ring Research Institute’s outer shell had deteriorated because of material shortages.

Ch. 360The Story of a Ship

Bo You searched for autunite to repair the Ring Research Institute, but discovered that an unknown opponent had already taken it from the past. After learning that an ancient scholar and a bald monk had removed the mineral, he left the site with his researchers, still unsure who was opposing him through time.

  • Bo You explained his damaged ship to a boy and repaired the boy’s wooden toy boat.
  • A researcher told Bo You that the site’s autunite had been dug up before the Ring Research Institute arrived.
  • Bo You concluded that someone was opposing him across time and questioned how Qin Yiguan could be involved in Lu Guang’s death.
  • The boy’s parents told Bo You that an ancient scholar and a bald monk had taken the minerals using a wooden machine.
  • Bo You warned the parents to take their child away from the radioactive soil, then departed with the researchers aboard the Ring Research Institute.

Ch. 361The Broken Vehicle

Bo You discovered that Qin Yiguan and his allies had taken the Ring Research Institute’s needed materials across different eras, while the institute’s neglected condition and dwindling supplies caused it to deteriorate. Bo You collapsed after repeated reports of empty landings, and the staff said his body needed to be replaced.

  • Bo You learned from the Jiajing Emperor that a scholar and a monk had taken the Nine Dragons Golden Elixir he sought.
  • Jiang Yizhou told Qin Yiguan that he had gathered and sealed the requested materials, and Qin Yiguan said he would collect everything on the list before the Ring Research Institute could.
  • Bo You heard that the institute was badly worn from time travel and nearly out of supplies.
  • Bo You received repeated reports that the materials at their landings had already been taken, including a report that the only resin found had gone to the sewage system.
  • Bo You coughed up blood and collapsed, and medical staff said his cancer had spread and his body needed to be replaced.

Ch. 362Revisiting an Old Haunt

Qin Yiguan traveled back to the Republican era and met six-year-old Fu Bo You, the future director of the Ring Research Institute. Twenty-two years later, the elderly Bo You discovered that his childhood home held no trace of his life and wondered how his past had been changed without erasing his memories.

  • Qin Yiguan arrived with Jiang Yizhou and Shitian at the place where the torbernite had been hidden, while Liu Quan C and Liu Shuan Q got stuck in the vortex.
  • Qin Yiguan approached a boy playing by a puddle and learned that he was Fu Bo You.
  • Qin Yiguan revealed that the updated institute list identified Fu Bo You as its future director, and he decided to act twenty-two years before Fu Bo You joined the institute.
  • Qin Yiguan hypnotized Fu Bo You's parents and took the six-year-old through a blue vortex, convincing them that a secret government organization would train him.
  • Twenty-two years later, elderly Bo You woke in his wheelchair at his parents' house, found no trace of his life there, and feared that someone had changed his past.

Ch. 363Unofficial Employee

Bo You hid the Ring Research Institute’s weakening emblem and his failing health while investigating a suspected traitor and the institute’s hidden engine. He entered the engine chamber and revealed a bound young man he identified as Qin Yiguan.

  • Gu Wu proposed killing a younger Qin Yiguan, but Bo You insisted Qin was not responsible and forbade Gu Wu from targeting him.
  • A level 2 employee brought in the institute’s plaque, revealing a fading gap in its blue ring emblem that alarmed Bo You.
  • The medical department head suggested the institute might have a founder or leader above its level 10 director, Bo You.
  • After the others left, Bo You concealed his panic, suspected a traitor, and entered the secret corridor leading to the institute’s engine.
  • Bo You reached the engine chamber, where laser lines restrained a young man, and greeted him as Qin Yiguan.

Ch. 364Diligence

Bo You revealed that the cloned Qin Yiguan had been guiding the original Qin Yiguan through time to collect the Ring Research Institute’s repair materials, which Bo You had secretly planned to obtain. Qin Yiguan and Jiang Yizhou stored another haul in Zhao Kuangyin’s palace and set out to find the final, exceptionally difficult material.

  • Bo You explained that he had cloned Qin Yiguan and modified the clone with time-related abilities taken from Song Miao, Lu Guang, and Jiang Yizhou.
  • Bo You revealed that Qin Yiguan had collected the Ring Research Institute’s materials across repeated journeys and hidden them in Zhao Kuangyin’s imperial palace.
  • Jiang Yizhou and Qin Yiguan sealed another warehouse of materials beneath the palace.
  • Qin Yiguan checked Song Miao’s list and found that only one material remained.
  • Jiang Yizhou and Qin Yiguan decided to travel together to obtain the final material, which might be collectible only by Qin Yiguan.

Ch. 365The Only Material

Bo You revealed how a time-traveling Qin Yiguan clone sustained the Ring Research Institute's repeated material-gathering cycles, though unexpected changes troubled him. Jiang Yizhou led Qin Yiguan and Shitian toward the source of the acoustic levitation equipment the institute needed.

  • Bo You recalled creating a time-traveling Qin Yiguan clone to place the Ring Research Institute in gaps in time and enable repeated material collection.
  • Bo You worried about leaked information and his missing six-year-old self before reassuring himself that his final trump card could reverse any failure.
  • Jiang Yizhou took Qin Yiguan and Shitian past the Great Pyramid of Khufu and into Jarl's office in Sweden in 1940.
  • Jiang Yizhou played footage of Tibetan monks levitating stones with musical instruments and identified acoustic levitation as the secret behind pyramid construction.
  • Qin Yiguan identified acoustic levitation equipment as the institute's hardest material to obtain and questioned how Jiang Yizhou knew only he could obtain it.
  • Jiang Yizhou traced the institute's equipment to Edward's megalithic estate in Florida, and Qin Yiguan stepped into a blue vortex to continue the search.

Ch. 366World of sound

Qin Yiguan and Jiang Yizhou visited Edward's Megalithic Manor to investigate the stone gate and uncover the acoustic levitation technology hidden within it, but Qin Yiguan found no clues. When the Boundless One appeared, Qin Yiguan followed its trail and entered a world formed from sound waves, where the words “Sound Universe” appeared.

  • Qin Yiguan and Jiang Yizhou examined Edward's enormous stone gate, but Qin Yiguan initially decided to leave because the Ring Research Institute had failed to discover its secrets.
  • Jiang Yizhou urged Qin Yiguan to try again, and Qin Yiguan used his abilities to inspect the gate and its ordinary-looking bearing, finding nothing unusual.
  • Taotie Gala told Qin Yiguan that someone had mailed him a gift and sent a picture of a crystal ball depicting a woman being pressed into a lake; Qin Yiguan hid his reaction and returned his attention to the gate.
  • The Boundless One appeared before the gate, and Qin Yiguan followed the silhouettes it left behind as the manor's surroundings dissolved into blue sound-wave outlines.
  • Qin Yiguan found himself in a world reconstructed from sound waves, where the words “Sound Universe” appeared and identified it as a parallel universe coexisting with reality.

Ch. 367Beyond Understanding

Qin Yiguan entered the Boundless One’s universe of sound and found the hidden material the Ring Research Institute needed by opening a massive stone door. After the materials were assembled beneath the Song Dynasty palace, the Institute suddenly crashed into Bianjing.

  • The Boundless One revealed itself as a sound-formed figure resembling Qin Yiguan and guided him through the sound universe.
  • Qin Yiguan used tapping and his heightened perception to align two sound waves, open the stone door, and recover two tiny black specks.
  • Jiang Yizhou identified the specks as the material sought by the Ring Research Institute and stored them in a wooden box.
  • Qin Yiguan and Jiang Yizhou brought the gathered materials to the underground ice chamber beneath the Song Dynasty palace.
  • A white building crashed from the sky into Bianjing, shaking the palace and startling the guards.

Ch. 368The Plan

Qin Yiguan, Jiang Yizhou, and Shitian confronted Bo You after the Ring Research Institute arrived in the Song Dynasty. Bo You revealed that he had come to kill Qin Yiguan and had prepared a clone for the task.

  • The Ring Research Institute emerged behind a blue plasma shield, and Bo You greeted Qin Yiguan as a former field-team employee.
  • Shitian denied that any of Bo You’s employees were present, while Jiang Yizhou crossed over to stand beside Bo You.
  • Bo You said he planned to kill Qin Yiguan while continuing to exploit the repeating past to collect materials.
  • Bo You explained that he had noticed changes in Qin Yiguan’s actions and intended to stop his cycle of time.
  • Bo You revealed that the Ring Research Institute had created two successful clones of Qin Yiguan and implanted a mental illness in one to kill him.

Ch. 369Cloning

Bo You triggered Shitian’s Slaughterer Higher Self to attack Qin Yiguan, but Qin exposed Jiang Yizhou’s betrayal and used Timeline Convergence to escape the killing blow. The materials were gone, and Bo You was left demanding to know what Qin had done.

  • Bo You revealed that Shitian’s mental disorder could be triggered and commanded him to kill Qin Yiguan.
  • Shitian’s Slaughterer Higher Self appeared and attacked Qin, while Qin’s Victim shattered and his Guardian struggled to block the cleaver.
  • Bo You’s researchers opened the ice chamber, but found that all the materials were missing.
  • Qin accused Jiang Yizhou of failing his tests and explained that his eagerness to collect the materials had exposed him.
  • Qin activated Timeline Convergence, causing the Slaughterer to disappear and leaving Qin unharmed.
  • Bo You checked himself, the researchers, and the Ring Research Institute, found them unchanged, and demanded to know what Qin had done.

Ch. 370Breaking Free of the Shackles

Qin Yiguan explained how Moment-of Time let him alter events before the Gemini Superbrain’s delayed timelines converged. After freeing Jiang Yizhou from the Ring Research Institute’s control, he confronted Bo You, who fled back into the institute.

  • Qin Yiguan said he had discovered a delay between cause and effect when Lu Guang died, and used Moment-of Time to change events before timelines converged.
  • Qin Yiguan revealed that Shitian had torn out his own eardrums so he could not be used by Bo You or hear his commands.
  • Bo You ordered his people to retreat into the institute, but Jiang Yizhou refused to flee and declared he would no longer be controlled.
  • Qin Yiguan recalled visiting Jiang Yizhou twelve hours earlier and learning he wanted to see the woman he loved again, while a collar restricted his ability.
  • The timelines converged, giving Jiang Yizhou new memories and freeing him from his restraints; Bo You escaped into the Ring Research Institute.

Ch. 371The Founder

Bo You sought the Ring Research Institute’s hidden founder as the institute spiraled out of control. The founder’s office appeared, and Bo You was horrified to recognize the young man inside as he announced, “Timeline Convergence!”

  • Bo You fled into the secret chamber’s dark corridor while Qin Yiguan stayed in the square.
  • Bo You saw that the institute’s ring emblem had broken and begged the absent founder to help.
  • Bo You cursed the founder and threw away the nameplate, causing its emblem to glow and repair itself.
  • The founder’s office appeared, and Bo You retrieved the nameplate before crawling inside.
  • The founder turned around, leaving Bo You speechless with horror, and declared, “Timeline Convergence!”

Ch. 372The Ship of Theseus (I)

Qin Yiguan revealed how he used the Ring Research Institute’s materials, blueprints, and a younger Bo You to create a new institute and reshape its history. After the fourth Timeline Convergence, Bo You’s former researchers stood with Qin Yiguan, while the doctor he trusted was revealed to be Song Miao.

  • Qin Yiguan brought a newly built Ring Research Institute out of a time-space vortex as Bo You’s original institute vanished.
  • Qin Yiguan explained that he had used the gathered materials and Song Miao’s blueprints to build a replacement institute in 2122.
  • Qin Yiguan revealed that he had raised Bo You’s six-year-old self into a scientific genius who managed the new institute and recruited its members.
  • The fourth Timeline Convergence shifted the white-coated researchers to Qin Yiguan’s side, with their past hostility diminished.
  • Bo You sought medicine from his doctor, but she removed a chip-embedded silver needle and revealed herself as Song Miao.

Ch. 373The Ship of Theseus (Part Two)

Song Miao revealed how she helped Qin Yiguan engineer the Research Institute’s timeline and expose Bo You’s past. Qin Yiguan then used Logic Fracture to make Bo You suffer a fatal illusion of suffocation and disclosed that the Institute’s time-traveling members had abandoned their real bodies for digital selves in the Metaverse.

  • Song Miao explained that she disguised herself as Bo You’s physician, poisoned him, and helped Qin Yiguan’s replacement plan proceed.
  • Bo You pretended that Timeline Convergence had reset him, but Qin Yiguan revealed he had used Logic Fracture on Bo You instead.
  • Qin Yiguan imposed the memory and sensation of a worsening fire injury on Bo You, who began to suffocate and panic.
  • Qin Yiguan revealed that the Institute’s original members were brain-dead in the real world and that their Metaverse selves were Digital Humans carrying implanted memories.
  • Bo You collapsed and died while suffocating under Qin Yiguan’s imposed illusion.

Ch. 374Setting Sail Again

Qin Yiguan freed the Boundless One, whose true body fused with him and unlocked new abilities, then set the Ring Research Institute on a course through history with Jiang Yizhou as its power engine. As Shitian left to explore the world, Qin Yiguan sent him a farewell message.

  • Qin Yiguan released the Boundless One, who entered him and completed their fusion, granting the abilities Moment-of Time and Logic Fracture.
  • Jiang Yizhou offered to power the Ring Research Institute and introduced Qin Yiguan to Su Xiu, a Digital Human modeled on his late lover.
  • Jiang Yizhou revealed that he had once taught Qin Yiguan history at 053 High School in Mirage City.
  • Qin Yiguan instructed the Digital Humans to explore history and told Jiang Yizhou to avoid disrupting established chains of cause and effect.
  • Shitian chose to travel alone and said he would try to return the Slaughterer inside him to Qin Yiguan.
  • Qin Yiguan used God's Abandoned to project a screen telling Shitian to go already.

Ch. 375Images of the Past

Qin Yiguan used the Boundless One’s Consciousness Flashback to revisit the night his mother died and discovered that clones of his adoptive parents had drowned her. He returned to the memory to learn what happened to her body, but the chapter ended before he could read the stone marker.

  • Dr. House reunited with his beloved after a visitor arrived at his clinic, completing the Virtual Ring Research Institute event and raising the Separation Rate by 12%.
  • The Boundless One offered Qin Yiguan a Consciousness Flashback, and Qin chose to revisit the night his mother died.
  • Inside his six-year-old self’s memory, Qin saw a man and woman identical to his adoptive parents drown his mother, revealing them as Bo You’s clones.
  • The Boundless One’s body partially dissipated as Qin returned to the Metaverse, and Qin asked to revisit the memory to find out what happened to his mother’s body.
  • Qin saw a man resembling his adoptive father bury his mother and raise a stone marker before his adoptive parents appeared and offered to take him home.
Arc 15 of 25
Arc 15 of 25