Little Illyana sleeps inside Mondo's rocky stomach, lulled to sleep by the soft humming of the gentle giant. She wakes up unaware of her surroundings and sees a sliver of light in front of her. She reaches toward the light, piercing her hand through the rocky exterior. Mondo, in disguise, walks past the guards to bring Illyana to safety when a small hand bursts forth from his chest. One of the guards catches the anomaly and notifies his friend of it. A meek voice cautiously calls from Mondo's stomach and he quickly slaps his hand on his chest to silence the girl. A hand taps on Mondo's shoulder and he turns around to see the suspicious glare of the first guard.
"Quietus" stands in the piercing gaze of Sugar Man who is holding the recently dead body of Chamber. Quietus nervously rants to Sugar Man about the suspected intruder into The Core and now they can all relax since the intruder is dead. Sugar Man isn't pleased; all that he has to show for the commotion of the break-in is one dead mutant. He says that if he were the intruder, he would not break into a huge instillation like The Core without back up. Sugar Man believes that Quietus is pulling an inside job. He screams at Quietus right before he impales his stomach with his razor sharp tongue.
Sugar Man retracts his tongue and a thick green mist pours out of the wound. He mocks Quietus, saying that he thought that he was more solid. Sugar Man quietly fascinates over the fact that two mutants were posing as one. Skin tells Husk that she should shed the Quietus form due to her extensive bleeding, and she agrees. She husks into her normal form, revealing her mission and her affiliation to the Sugar Man. He screams at his underlings to kill Generation Next.
An incredible explosion rocks the ceiling, burying the numerous underlings heading toward the team. They are shocked and baffled, but Chamber, raised from the dead, explains that it was Colossus and Shadowcat coming to rescue them. He then goes on to say that he wasn't really dead; he used his psionic abilities to trick everyone in the room into thinking that he had been shot. Chamber orders his team to find Illyana and get out. One of the underlings reaches for Chamber while his back is turned but he is dropped dead by a quick jab through the head by one of Skin's extensions. Chamber tells his friend that he is disgusting, but the Sugar Man saying that he is going to go for back up cuts their conversation short. Chamber releases a savage blast of bio-kinetic energy, liquefying Sugar Man to a pile of pulp. Skin then returns Jono's disgusting accusation and notices that Chamber looks worried. Skin asks his friend why and he answers that he is feeling a bit paranoid. Husk, holding the unconscious body of Vincente, is surrounded by a group of underlings about to attack her.
Suddenly appearing, Colossus squashes the underlings, then gives Chamber and Skin the order to find his sister, Illyana. Out of the remains of the Sugar Man emerges a minute duplicate that overhears Colossus talking about his little sister. Sugar Man burrows down to the lower levels to find her before the team can reach her.
Down below, Mondo is being severely beaten by the guards that ruined his cover. Mondo asks them to stop it but the other guard tells his friend not to stop until Mondo tells them whom he is working for. Mondo gets frustrated with the guard and quickly absorbs himself into the cliff side, launching the guard over the edge. The other guard looks questioningly at the cliff, trying to figure out where Mondo went. Mondo materializes behind the guard and pushes him off of the cliff as well. Ace comes up behind Mondo, asking him to take her with him, since he had promised to come back for her before. Mondo says that he will try, much to Skin's disappointment. Skin says that it is not their place to liberate Ace since their mission was to only free Illyana. Chamber agrees. Skin then asks Mondo what he did with Illyana and Mondo begins to tell his friends but stops mid-sentence to spit up blood. A long sinuous tongue slowly rips its way through Mondo's rocky flesh, tearing him in half and stealing Illyana from her safe hiding place. Sugar Man asks the youngsters what all of the fuss is over one little girl; all of Magneto's careful planning would be ruined if he decided to swallow her whole.
A defiant scream echoes from the roof as Colossus plummets down upon Sugar Man's head, beating him over and over again until he is just a mass of blood bone and flesh. Colossus takes his sister in his arms, telling her everything will be all right. Ace says that Mondo said the same thing to her. Chamber takes her in his arms as Husk meets up with the team carrying Vincente on her back. The team heads toward the exit.
The main room is a battlefield, the humans revolting against their mutant oppressors. The mutant guards call for back up. The team is disheartened at the horrific sight but Colossus tries to rally them together to reach the doorway. A mutant guard comes up behind Colossus, reaching for Illyana. Shadowcat phases out of her husbands back and kills the attacker, boosting the moral of the frightened team. Chamber telepathically orders Skin to take Ace from him before it is to late, but Skin isn't quick enough. Chamber is dragged into the seething mass of people along with Ace and Skin jumps in after them. Shadowcat tells the rest of the team to go on; she will go after the boys. However Colossus stops her, saying that it is their duty to bring Illyana to Magneto first and then they can come after the children. Shadowcat protests but her husband insists. Husk screams at them not to leave them now, since Vincente has stopped breathing. Shadowcat turns her husband, Illyana and herself intangible, floating them through the ceiling just as the mutant guards reinforcements arrive.
Right outside The Core, Shadowcat returns to tangibility, dropping off her husband and Illyana. Colossus demands to know what is going on and she tells him that they are clear of The Core and Colossus can take his sister to Westchester now, but she is going back for the students. Colossus objects, shoving his sister into Shadowcat's arms telling his wife that he will go and retrieve the students. He jumps down to the main entrance as Shadowcat airwalks Illyana to safety.
Colossus crashes into on the two guards at the entrance, not even pausing as he takes off down the corridor to the entrance. The door starts to close and Colossus dives to try to stop its closing. He valiantly pushes with all of his strength, catching a final glimpse of Husk overwhelmed and outnumbered. The underlings are taking her down but she still fights back by husking her arm into a form of bio-energy. The evil mutants overwhelm her and she is buried in a sea of writhing bodies. The door snaps shut in front of Colossus' watching eye, leaving him to wallow in his self-pity. He collapses in front of the door and cries.
As night falls outside of The Core, Shadowcat waits for her husband's return by a fire. He comes up behind her all alone. When Shadowcat questions him about the missing students, he says that he did all that he could and sits down to warm himself by the fire. In the silent glow of the moon, Sugar Man peeks out from his hiding place in the boot of Colossus. He stares into the fire and grins.