Chapter Summaries

Grindelwald established a camp in a cleared section of the Forbidden Forest, prompting centaur Fernandis to warn Mr. Ogg about the forest’s destruction and the imported Dark Creatures. In the Chamber of Secrets, Li Weide continued his Basilisk-breeding experiments and discovered that an Obscurus could restore itself by consuming magical residue, leaving him with a new explanation for why unhosted Obscuruses disappeared.

• Mr. Ogg led Grindelwald to a large clearing filled with workers, a tent, Thestral Carriages, and crates holding Dark Creatures.
• Centaur Fernandis confronted Mr. Ogg about the damage to the forest and the threat the Dark Creatures posed to its balance, then agreed to wait for Hogwarts’s reply.
• Li Weide explained that he was breeding a small number of carefully raised roosters to pursue a Basilisk-breeding industry, and Slytherin berated him for not raising them in greater numbers.
• Li Weide noticed that the Obscurus had regrown where he had cut it and that the preservation magic had weakened.
• Li Weide fed the Obscurus pure residue and saw it consume some, regain solidity, and reveal that an Obscurus needed nourishment to survive.

Li Weide experimented on an Obscurus and used its magic to create robes that let Slytherin touch objects and cast spells again. Slytherin delighted in regaining magic, while Li Weide teased him about returning to his former arrogant manner.

• Li Weide tested how the Obscurus could be divided and restored, then stored it in a Goblin Metal container and fed it pure Residue.
• Li Weide discovered that the Obscurus's severed magic was difficult to absorb and decided to use it to make something for Slytherin.
• Li Weide found Slytherin sulking inside his statue and covered him with robes made from Obscurus magic.
• Slytherin discovered that the robes let him touch parchment and hold a wand, then used the Levitation Charm to lift the papers.
• Li Weide explained that the robes would last about three months before needing to be remade, and Slytherin warmly thanked him.
• Li Weide teased Slytherin that he preferred him arrogant and unyielding, and asked him to return to that manner.

Slytherin defeated Li Weide in a vicious duel, then explained how ruthless tactics could let a weaker wizard overcome a stronger one. After two hours of training, Li Weide eagerly planned ways to combine enchanted Muggle weapons with magic, leaving Slytherin wondering what sort of demon he had unleashed.

• Slytherin challenged Li Weide to a duel and petrified him after controlling the fight with deadly curses and strategic tricks.
• Li Weide realized Slytherin’s ruthless, initiative-seizing approach differed from Dumbledore’s calculated dueling techniques.
• Slytherin described using hidden crossbows and poisoned canes, inspiring Li Weide to consider guns and Chinese Chomping Cabbages for combat.
• Li Weide and Slytherin continued fighting for two hours, and Li Weide replenished the magic in Slytherin’s Wizard Robes with the power of the Obscurus.
• Slytherin taught Li Weide a magical rune to help Muggle weapons pierce powerful wizards’ defenses, and Li Weide began planning enchanted, venom-coated bullets.

Li Weide learned that Grindelwald planned to test students by making them face dangerous creatures in the Forbidden Forest, and decided to secretly take some creatures for his own research. He left Tom curious about the mysterious box from Tom’s father and uneasy about Li Weide’s plan.

• Li Weide explained to Tom how to phrase a cookbook gift so House-elves would accept it, then charmed Nearly Headless Nick with a compliment about his beard.
• Tom received a letter and a box from his father, and Li Weide pocketed the box, promising that he had prepared something for Tom too.
• Annie arrived with news, and Li Weide taught her the Whispering Charm so the three of them could communicate without speaking aloud.
• Annie told Li Weide and Tom that Grindelwald had built a tent in the Forbidden Forest filled with dangerous Dark and Magical Creatures for student assessments.
• Li Weide concluded that Grindelwald was preparing students for practical combat and announced that he intended to borrow some of the creatures.

Dumbledore met with Fernandis to discuss restoring the forest and protecting it, but an attack on centaurs by Grindelwald's Followers derailed the talks. As Fernandis led a rescue party and Dumbledore followed, Grindelwald discovered that his subordinates could not remember the identity of the person who had urged them to attack.

• Dumbledore visited the centaur settlement and promised Fernandis he would negotiate with Grindelwald about restoring the forest and preventing Dark Creatures from entering.
• A wounded centaur reported that Grindelwald's Followers had attacked the centaurs and captured Filen and others, prompting Fernandis to lead a rescue party.
• Dumbledore joined Fernandis, hoping to learn what had happened and prevent the conflict from worsening.
• Grindelwald found the captured centaurs tied together and demanded to know which of his Followers had started the fight.
• The Followers said an associate had urged them to attack, but they could no longer remember his name or clearly recall his appearance.

Gellert Grindelwald investigated a clash between his Followers and the centaurs, but Legilimency showed that every group’s contradictory memories were genuine and unaltered. He asked Dumbledore to examine the witnesses too, and Dumbledore was left just as confused.

• Grindelwald questioned the Followers and the centaurs, who gave conflicting accounts of who had started the fight and whether Dark Creatures had been released.
• Grindelwald used Legilimency on the witnesses and found that their memories were genuine, including memories of an inexplicable person who appeared to be absent.
• Grindelwald checked the carriage and the tent and found the Quintapeds in the tent, despite the centaurs’ memories saying they had been released into the Forbidden Forest.
• Fernandis arrived with Dumbledore and accused Grindelwald’s Followers of harming the centaurs, while Grindelwald blamed the centaurs for releasing Dark Creatures and attacking first.
• Grindelwald invited Dumbledore to inspect the Followers’ memories, and Dumbledore discovered the same bizarre contradictions and shared Grindelwald’s confusion.

Dumbledore and Grindelwald investigated the strange visions affecting the Dark Creatures while tensions with the centaurs escalated into a fight. Dumbledore discovered that the collision of different Dark Arts had created chaotic magic resembling the Ancient Magic he had seen on Li Weide.

• Dumbledore tried to negotiate with Fernandis, but Grindelwald insulted and threatened the centaurs until Fernandis and his kin attacked.
• Grindelwald stopped the arrows with magic, and Dumbledore knocked the centaurs unconscious before they could be killed.
• Dumbledore and Grindelwald checked the tent and surrounding area, finding no missing Dark Creatures but discovering dense, chaotic magical traces.
• Dumbledore ordered Grindelwald to send the Dark Creatures home and suspend his trial, but Grindelwald refused and suspected Dumbledore's side might be responsible.
• Dumbledore privately recognized that the colliding Dark Arts had produced chaotic magic resembling the Ancient Magic he had seen on Li Weide.

Li Weide revealed that his magically enhanced revolvers could shatter Tom’s Shield Charm, then joined Dumbledore to investigate a strange magical force in the Forbidden Forest. He remotely controlled an Obscurus as a drone and prepared to investigate the forest, with Slytherin in mind as a companion.

• Li Weide opened a box containing two revolvers engraved with magical runes and demonstrated their power by destroying a shielded wooden target.
• Tom took a revolver and bullets, while Li Weide offered to make Annie one and explained that submachine guns would have to wait for an ammunition assembly line.
• After the trio finished testing the guns, Dumbledore took Li Weide aside and told him about strange events in the Forbidden Forest that might involve a force resembling Ancient Magic.
• Li Weide connected the force to the missing Senior Sister and proposed investigating the Forbidden Forest, while Dumbledore warned him that it was dangerous.
• Li Weide used Nightmare Magic to attach part of his consciousness to an Obscurus and control it remotely, planning to send it into the Forbidden Forest and bring Slytherin along.

Li Weide and Dumbledore used the Obscurus to investigate the chaotic magic above Grindelwald’s tent, where they found a vast concentration of Ancient Magic. As they approached the vortex, an invisible attacker struck them, and the chapter ended when both Disillusionment Charms failed and revealed an identical Obscurus.

• Dumbledore asked Li Weide to scout ahead with the Obscurus and shared its senses so they could communicate during the investigation.
• Li Weide flew the Obscurus to Grindelwald’s tent, where he and Dumbledore saw deep-blue Ancient Magic mixed into the surrounding Dark Arts magic.
• They spotted a colorful vortex above the tent and cautiously approached it, while Li Weide considered how to purify and absorb the abundant Ancient Magic.
• The Obscurus collided with an unseen presence, and an attacker cast a spell that Li Weide dodged before counterattacking.
• Both attacks missed, and when their Disillusionment Charms failed, Li Weide and Dumbledore saw that the other presence was an identical Obscurus.

After encountering an identical Obscurus near Grindelwald’s camp, Li Weide and Dumbledore debated whether it was a time-traveling double or an illusion. The Marauder’s Map then showed a follower’s name duplicating, and Dumbledore went to investigate as Grindelwald approached the Forbidden Forest.

• Li Weide and Dumbledore fled the matching Obscuruses after their spells failed to connect, escaping Grindelwald’s followers.
• Dumbledore suggested the other Obscurus might be their past selves, while Li Weide questioned whether everyone had shared an illusion.
• Li Weide checked the Marauder’s Map but found no other copies of himself or Dumbledore; the map showed Grindelwald’s followers near their tent and Fernandis’s centaurs migrating deeper into the forest.
• Li Weide and Dumbledore saw the follower Best William’s name briefly appear twice and then three times before returning to one.
• Grindelwald appeared on the map moving toward the Forbidden Forest, and Dumbledore left to investigate the duplication himself.

Dumbledore borrowed the Marauder’s Map after discovering a startling name on it, while Li Weide hurried him toward the Forbidden Forest to give Slytherin time to clear the Chamber of Secrets. At the forest, the group witnessed inexplicable duplicates, and the chapter ended with a second Grindelwald appearing with the Elder Wand.

• Dumbledore saw something shocking on the Marauder’s Map, borrowed it from Li Weide, and left without explaining what he had found.
• Li Weide realized Dumbledore might have spotted Salazar Slytherin’s name and persuaded him to visit the Forbidden Forest first.
• Slytherin received Li Weide’s warning, cleared the Chamber of Secrets, and escaped with his suitcase of little roosters.
• Dumbledore and Li Weide reached the forest and heard Best and Grindelwald’s Followers describe three versions of Best, one of whom had wounded him.
• A duplicate Grindelwald appeared and exchanged Killing Curses with Grindelwald before vanishing; Li Weide revealed that the double had been holding the Elder Wand.

Dumbledore, Grindelwald, and Li Weide stopped the strange appearances by separating the Dark Creatures, then Li Weide proposed that the doubles came from parallel worlds. He explained how alternate timelines could create similar but different worlds, and Dumbledore and Grindelwald began to understand the possibility.

• Grindelwald realized that the double he had fought wielded a genuine Elder Wand, while Dumbledore confirmed that his own wand was real.
• Li Weide proposed separating the Dark Creatures, and Grindelwald ordered his Followers to move them into groups five hundred meters apart.
• The chaotic Magic Field and the strange incidents stopped after the Dark Creatures were dispersed.
• Li Weide suggested that the doubles came from parallel worlds and explained how changes to a timeline could produce similar worlds with different histories.
• Dumbledore and Grindelwald connected Li Weide's explanation to the differences between the doubles, including Grindelwald still possessing the Elder Wand in the other world.

Li Weide and Grindelwald concluded that overlapping Parallel Worlds could switch people and gradually erase memories of people or objects that did not exist in their new world. After Dumbledore ordered them to stop investigating, he found fresh chicken droppings in the Chamber of Secrets, where Slytherin had disappeared.

• Li Weide explained that people from overlapping Parallel Worlds could be switched, and Grindelwald connected the theory to his followers’ fading memories of a mutual friend.
• Grindelwald discovered that Gottfried Martin’s wand was Cherry Wood instead of the Ebony Wand he remembered giving him, leading Li Weide to conclude that the followers had come from another world.
• Dumbledore ordered Grindelwald to disperse the Dark Creatures and told Li Weide to stop researching Parallel Worlds.
• Dumbledore checked the Marauder’s Map, noticed that Slytherin had disappeared from the Chamber of Secrets, and went there to investigate.
• Dumbledore found fresh chicken droppings beside a stone pillar in the dark Chamber of Secrets.

Li Weide explained that Senior Sister’s memories and name vanished because a Parallel World exchange replaced her body while her soul remained behind. Senior Sister learned that the body in the Crystal Coffin belonged to her counterpart from another world, and her original body was gone.

• Li Weide told Senior Sister about the Forbidden Forest incident and his theory about Parallel Worlds.
• Senior Sister recalled that her Nightmare Magic had let her soul leave her body shortly before her consciousness was attacked and her name disappeared.
• Senior Sister revealed her body in the Crystal Coffin, and Li Weide found physical differences between it and her soul’s form.
• Li Weide concluded that a magical backlash had exchanged Senior Sister’s original body for her Parallel World counterpart, leaving her soul behind and erasing her original memories and name.

Li Weide and Slytherin investigated the strange disappearance of Slytherin’s remains and realized that Slytherin could learn spells created centuries after his death. The chapter left Slytherin wondering whether his body was still alive and whether someone had used him in an immortality experiment.

• Li Weide woke from a nightmare, and Tom avoided his offer to practice by putting himself to sleep with a spell.
• Li Weide returned to the Wizard Tower and told Slytherin about the day’s strange events and Dumbledore discovering him.
• Li Weide noticed Slytherin was reading a book from a later era, and Slytherin demonstrated a Dark Arts curse he had just learned.
• Li Weide pointed out that ghosts could not learn new knowledge, prompting Slytherin to question whether he was truly dead.
• Li Weide suggested Slytherin’s remains might never have been in the coffin, and Slytherin wondered if his body was still alive and had been used in an experiment.

Li Weide and Slytherin investigated Slytherin’s grave and discovered that the empty stone coffin may have been used to seal his soul. Ancient Magic in the tomb pointed toward an Ancient Sage, but Slytherin had forgotten the sage’s identity and insisted the sage could not have been responsible.

• Slytherin dug open his grave, and Li Weide joined him to inspect the stone coffin.
• They found that the coffin was empty and bore incomplete runes that Slytherin dated to a thousand years ago.
• Li Weide proposed that the coffin had sealed Slytherin’s soul, and Slytherin agreed that the idea explained his memories.
• Li Weide found traces of Ancient Magic in a stone brick, suggesting the Ancient Sage might have built the tomb.
• Slytherin admitted he had forgotten the sage’s name and details, but insisted the sage would never have done this.

Li Weide helped Slytherin use an improved Obscurus garment to regain a body-like form, and Slytherin revealed he planned to leave Hogwarts to uncover the truth about what happened to him. Dumbledore found them in the Forbidden Forest, discovered Li Weide’s hidden Wizard Tower, and asked to hear their story.

• Li Weide finished improving the Obscurus garment, allowing Slytherin to touch objects and use magic in a solid-looking body, though he still could not eat.
• Slytherin told Li Weide he planned to leave Hogwarts and investigate the truth behind his fate on his own.
• Li Weide and Slytherin walked through the Forbidden Forest and sensed a powerful presence behind them.
• Dumbledore appeared and explained that he had found them by expanding the Marauder’s Map to cover the Forbidden Forest.
• Slytherin admitted he had asked Li Weide to keep his existence secret, and Dumbledore questioned how he could look alive while being called a ghost.
• Li Weide shrugged off Dumbledore discovering the Wizard Tower and asked him to tell his own story first.

Dumbledore learned more about Slytherin’s history and agreed to protect Li Weide from the mysterious enemy connected to Ancient Magic. He decided Li Weide needed harsher training, and Slytherin asked him to train Tom as well.

• Li Weide transformed his laboratory into a living room and explained to Dumbledore how he had acquired the house from Toby.
• Slytherin asked Dumbledore to protect Li Weide, who might be targeted because of his Ancient Magic talent, and admitted that Li Weide had changed his views about Muggle-born students.
• Slytherin planned to revisit places he had visited a thousand years earlier, while Dumbledore urged him to stay at Hogwarts and help protect Li Weide.
• Dumbledore announced that he would train Li Weide more strictly, and Li Weide tried to involve Tom in the training.
• Slytherin asked Dumbledore to train Tom too, since he was Li Weide’s close friend and could also be drawn into the danger.

Tom and Li Weide endured Dumbledore’s brutal combat training, then received permission to use Slytherin’s Study as a laboratory. As they planned to practice spells and grow magical plants there, Tom realized Li Weide might be preparing to raise a Basilisk.

• Dumbledore made Tom and Li Weide fight him in the Room of Requirement, then assigned them essays and another training session for the next day.
• Li Weide told Tom that Dumbledore had approved Slytherin’s Study as their laboratory, though he concealed the reasons behind the arrangement.
• Tom and Li Weide explored the renovated study, divided its basement between magical plants and spell practice, and wrote essays about their training.
• Dumbledore and Headmaster Dippet discussed protecting Li Weide and persuading Slytherin not to side with Grindelwald.
• Tom found Li Weide raising chickens in the study and was alarmed when Li Weide said he would find a toad.

Li Weide reassured Tom that he would pursue Basilisk breeding outside Hogwarts, then took him to Hogsmeade on a day off from Dumbledore’s training. Their visit ended with them unexpectedly meeting Dumbledore at the Hog’s Head Inn.

• Li Weide told Tom he planned to raise a Basilisk in a country where it was permitted, and later used Newt’s suitcase to begin altering its interior environment.
• Slytherin flew over the modern Muggle world, saw cities devastated by bombardment, and reconsidered his views about Muggles.
• After sleeping until noon, Tom ate a meal from Li Weide, who told him Dumbledore had given them the day off from special training.
• Li Weide took Tom through a secret passage to Hogsmeade, reassuring him that Dumbledore would tolerate their visit.
• Tom tried to flee when he saw Dumbledore at the Hog’s Head Inn, but Li Weide blocked him and pushed him inside, where Tom blamed Li Weide for bringing him.