The children of light continued through the cold halls, passing the huge forms of frozen dragons. They eventually came to a side-tunnel that led northward a short distance before opening into a cavern carved of ice. A white chimera stood behind a closed portcullis at the far end of the hall, watching the party malevolently. Beyond the monster the heroes could see a door with a great eye carved into it, and four ice statues, each missing a hand, stood in alcoves around the cavern's edge. Multiple warding runes were etched into the walls and floor of the room; Glace noticed a cluster of the symbols on one wall between two of the cold statues, signifying the focus of an arcane trap. A ghostly mist hovered above the ground, adding to the room's menace, and the party decided to explore more of the cave complex before entering the room.
As the heroes continued to follow the main corridor, they passed two more side-tunnels. They passed these and continued toward the east, sensing that the hall was sloping slightly downward. They eventually emerged into a large cavern made of worked rock and ice. Skeletons lay about the room, some partially or fully encased in ice, and the marks of shovels and picks suggested that somebody had been digging the corpses out of their frozen tombs. Among the various skeletons the party found the remains of a dragonborn, an amulet of Io still around its neck. Neri explained that she believed the body to be that of an exarch of Io, sent to this realm with the white dragons.
The party left the cavern strewn with the dead and retraced their steps to a passageway leading to the north. As they traveled down this hallway, several heroes began to hear a humming sound while others noticed a faint purple glow coming from a room ahead. The children of light soon arrived at a room hewn from the surrounding stone. An archway stood in the center of the chamber, surrounded by runes that shone with alternating purple and black light. Ember studied the runes and determined that the structure was a doorway, though it was unlike the portals the heroes had used to travel from realm to realm. Alec identified specific runes as warding symbols, designed to prevent use of the doorway without a specific magical item or key.
Returning to the main corridor, the party backtracked to the final unexplored tunnel they had passed. This hallway ended in a ledge about twenty feet above the floor of a massive cavern. The ground in this cave proved not to be stone, but a frozen subterranean lake. Demarung's sharp eyes picked out unusual structures far to the south and east of the ledge – two cages made of ice, each holding a prisoner. The party made their way down to the surface of the lake and traveled toward the southernmost cage. As they neared, they could see that both cages were built on a rocky shore and each held a bearded human, a race the party had heard of from the shadar-kai. When the men in the cages spied the children of light, they began to yell at them in a language that only Alec understood, but the meaning was clear to all: get off the ice! The group began to run as large forms appeared in the waters beneath their feet. Three massive swimming worms chased the heroes as they ran for shore, but Ember, Aria and Alec were too slow. As their companions watched from the rocks, the worms broke up the ice and attacked the dwarf, the gnome, and the elf as they struggled to stand on the shifting floes.
Demarung reacted first to the danger facing his allies and heaved an enchanted javelin at the nearest worm. Fas hurled a crystalline sphere at another, slicing the creature as it shattered as Alec gulped a potion for protection and cursed the two nearest beasts. One of the worms near Neri and loosed a burst of electricity, shocking the dragonborn. Its two companions moved toward the heroes trapped on the ice floe as Aria, singing a battle chant, positioned herself to strike if the creatures came near her. Glace's form faded and reappeared next to the worm nearest the shore. The avenger struck the beast with his flail, channeling divine power to hurtle both his enemy and himself onto dry land. Neri, positioned across the worm's huge body from Glace, sliced into the creature as one of the beasts in the water hit Aria and Ember with a shocking blast. The gnome immediately vanished from sight in reaction to the danger, while the dwarf summoned a wave of astral energy that lashed out at the two creatures near her. Back on shore, Demarung rushed the grounded worm and surged into a frenzy, slicing into the beast's flesh with two powerful swings of his sword. Badly wounded, the worm released another burst of lightning focused on the warden and Glace. While the avenger and the defenders focused on the beached monster, Fas teleported onto an ice floe to aid his trapped companions. The invoker summoned radiant fire that streamed toward the worms swimming in the lake, scorching one badly. Alec cursed the beast nearest himself, then leveled another spell at the worm on shore, chilling it with an attack of arcane cold. The enraged beast attempted to bite Demarung, but the warden deflected the worm's maw with his shield and Glace seized the opportunity to dart in and again bashed the creature with his chilling flail. A moment later another swing of the avenger's flail finished off the worm and he sprung onto a nearby floe to aid his allies. The two water-borne worms continued to attack the children of light farthest from shore. While one emitted another electrical blast at Ember and Aria, the other lunged at Ember and bit the dwarf, knocking her prone. Aria slashed into its slick hide with her sword, sliding Ember nearer and allowing her to attack the creature as well. Meanwhile, Neri leapt from one floating mote of ice to another until she stood with Aria and Ember just as a worm released a shocking burst that struck at the dragonborn and the dwarf. Ember responded by smashing into the creature and invoking divine power to heal herself, Neri, and Aria. The enraged worm reacted with another electrical bust before attempting to bite Neri, but the fighter blocked the attack with her shield. Demarung leapt onto a mass of ice as he flung his enchanted javelin into the worm nearest shore. Fas summoned a divine thunderbolt that blasted the same beast and Alec cursed it with a spell of deadly judgment. The worm submerged to swim toward its new attackers while its companion shocked Neri with an electrical blast. Aria uttered words of arcane healing that soothed the fighter's wounds. Neri patiently waited to find a weakness in the badly injured worm's hide and struck, slaying the creature. Ember stood and, seeing that Glace was wounded, whispered a healing prayer for him. The remaining worm surfaced near Alec and the two foes exchanged attacks, the warlock striking the worm with an eldritch blast as it shocked him twice with electrical discharges and bit him. Fas summoned a radiant hammer that burst upon the worm's head as Aria attempted to leap to the attack but fell short, slipping into the frigid lake. While the gnome swam to the nearest ice floe and climbed out of the water, Glace bashed the worm with a flurry of blows. Demarung finished off the monster with a powerful swing of his sword, releasing a thunderous smash as it impacted on the worm's head.
The children of light made their way to the rocky shore and quickly dried off. The caged human introduced himself as Koren. He told the party how he and his companion named Ebbis had been captured and brought here by a treacherous human once called Ven. The heroes freed the humans, who explained that they had lived through a timeless era with their people, exploring the mote of earth they lived on, and Ven had met with elementals who promised him power and immortality in exchange for building a portal to this place. Ven had taken the name Vecna and now served Erek-hus. Vecna had succeeded in extending his life beyond his own death by bringing humans here to sacrifice in foul rituals. The undead traitor now dreamt of godhood, and had the promise of Erek-hus that he would attain it. Vecna's servants continued to mine corpses out of the ice to fuel the unclean rites that would make their undead lord a god. The children of light freed both humans, who explained more about Vecna and his power. A powerful priest served the undead lord, who now hated all that was part of his previous mortal life. A previous priest named Kas had rebelled against Vecna, and during their battle the Kas had cut from his erstwhile master a hand and an eye – symbols the heroes had seen in the room with the manticore.
The children of light provided food and warmth for the humans as they shared their history. As time passed and the tales came to a close, Aria developed a sense of kinship and deep respect for the hardy race. Soon the bard's form lengthened and her glittering black orbs grew eye whites around colored irises, sparkling with human resolve and determination.