The morning mist, thick and milky white, enveloped the Mist Swamp completely. The Youth Guardian Camp had barely stepped onto the swamp's edge when their trousers became icy from the moisture. A Mu's New Sprout Sword, its scabbard adorned with Ice-Fire Entwining Pattern, glowed with a faint blue light—not a warning, but rather an absorption of moisture from the air, forming a weak "air-crystal" connection with the fragments of the Child Crystal Core at his waist. In A Ya's bag, besides the Child Crystal Core fragments and Symbiotic Fiber, there were several bundles of " Marsh Reed Stalk " (swamp-resistant plant stalks prepared in advance by Liya, hollow and capable of guiding mist) and a small jar of " Sac-Coagulating Gel " (made from swamp gelatinous plants, used to repair damaged plant capsules). A Shi's sandboard had been replaced with a "waterproof birchboard," marked with clues to the adjustment points recorded from the Sand Sea Hourglass, indicating that the swamp adjustment points were located in the " Marshheart Sac community around the Mist-Purifying Spring."
"Don't step on the black mud!" Loran suddenly grabbed A Mu's arm. A patch of blackish swamp mud beside his feet was bubbling with tiny bubbles. "That's a 'boiling mud zone' rich in marsh gas. You'll sink even faster if you step in!" Just then, the golden figure of the Icefield Wolf darted forward, digging a shallow trench in the mud with its claws—revealing several translucent plants with fist-sized sacs hanging from their tips. Faint mist flowed within these sacs; they were " Marshheart Sac." However, most of these Marshheart Sac were deflated, some even cracked open, the mist slowly seeping out and dispersing into pale gray smoke in the air.
"This is the Marshheart Sac? Why is it all broken?" A Ya crouched down, her fingertips gently touching one of the cracked sacs—a chilling sensation ran through her fingertips. The sac walls were as thin as cicada wings, and the edges of the crack were stained with very faint black marks, as if it had been corroded by something. A soft buzzing sound came from afar, and several small insects with pale green wings flew over, but they only circled once above the Marshheart Sac before quickly flying away—those were " Mist-Dwelling Insect," which were supposed to feed on the energy overflowing from the Marshheart Sac, but now they couldn't find an intact sac to stay in.
Following the distribution of the Marshheart Sac deeper into the swamp, the mist gradually thinned, and a faintly glowing spring appeared ahead—the " Mist-Purifying Spring." However, a thin layer of gray film floated on the surface of the spring, and the water was no longer clear. Even the Marshheart Sac that should have surrounded the spring were now just a few crooked and broken branches, the cores completely shattered in the mud.
"Who's touching the Marshheart Sac?" A crisp voice came from the reeds by the spring, and several people dressed in green and brown linen clothes emerged—their trousers rolled up to their knees, their calves covered in mud, and they held slender reed tubes with webs woven from the wings of Mist-Dwelling Insect wrapped around the ends. The girl in the lead had her hair in two braids, the ends of which were tied with pendants made of fragments of the Marshheart Sac. Her A Wu, the little guardian of the Marshspeech Tribe: "In the past two weeks, more than half of the Marshheart Sac has shattered, the Mist-Purifying Spring has become dirty, and the Mist-Dwelling Insect have all flown away—the elders of the tribe say that it was 'hard energy' (referring to the Child Crystal Core ) that ruptured the Marshheart Sac!"
Following A Wu through the reeds, we arrived at the settlement of the Marshspeech Tribe —the "Swamp Houses" built on high wooden stakes (constructed from swamp hardwood, with roofs covered in waterproof swamp reed leaves). An old man sitting on a stone bench by the spring was blowing air into the Mist-Purifying Spring through a reed tube. The reed tube in his hand was pale green and was the " Main Mist-Guiding Tube." Seeing the group, the old man put down the tube and sighed, " The Marshheart Sac is alive; it needs the moisture from the Mist-Purifying Spring to sustain it, the secretions of the Mist-Dwelling Insect to stabilize it, and the energy of the Child Crystal Core to 'fix' it—now the energy of the Child Crystal Core is too 'rushing,' tearing the membrane of the Marshheart Sac. Swamp gas is leaking out, polluting the spring, and the Mist-Dwelling Insect dare not come, so the cycle is broken."
A Mu walked to the Mist-Purifying Spring, dipping his fingertip in the spring water—it had a slightly astringent taste, and tiny bubbles rose to the surface, indicating leaked marsh gas mixed in. The fragment of the Child Crystal Core at his waist suddenly heated up, and the blue light from the scabbard brightened. The remaining fragments of the Marshheart Sac by the spring even trembled slightly. "The energy has nowhere to be stored, that's why the Marshheart Sac bursts!" A Mu suddenly understood, "We can't just repair the sac; we also need to cleanse the spring water and bring the insects back—if any one of these is missing, the chain won't connect."
The Marshspeech Tribe elder nodded. "We need to use the ' Mist-Guiding Sac-Mending Technique.' We use reed tubes to draw the mist from the Mist-Purifying Spring, you use the energy of the Child Crystal Core to fix the membrane, and then let the Mist-Dwelling Insect return to repair it—but now the spring is dirty, and we can't draw clean mist."