- Genoshan mutants
- Arthur Maddicks (First appearance)
- Sunfire (Shiro Yoshida)
- Feral (Maria Callasantos)
- Tusk (Cameo)
- Kangaroo (Frank Oliver) (Cameo)
- Marianna (Cameo)
- Mole (Cameo)
- Toad (Mortimer Toynbee) (Cameo)
- Arclight (Philippa Sontag) (Cameo)
- Forearm (Michael McCain) (Cameo)
- Copycat (Vanessa Carlysle) (Cameo)
- Carmella Unuscione (Cameo)
- Reaper (Pantu Hurageb) (Cameo)
- Blockbuster (Michael Baer) (Cameo)
- J3 Communications
- Trish Tilby (First appearance)
Henry Gyrich presents a televised diatribe against the dangers that mutants pose to ordinary humans, encouraging the ratification of the "Mutant Containment Bill". Charles Xavier (who seems to be ill from weeks of battling this legislation) arrives to oppose the suggestion. Gyrich voices his suspicion that Xavier - known for protecting mutants - could well be a mutant himself, and attacks him with a small device (an energy disruptor) that makes Xavier's powers go out of control and puts him in a coma. Gyrich himself is dragged away by police, raving that "normal-looking people who defend mutants are mutants themselves!" Cyclops, Wolverine and Beast rush to the Professor's aid.
On the Blackbird, Beast reveals that Xavier is still fighting to stay alive, and Cyclops radios the mansion to prepare the medlab and contact Moira MacTaggert on Muir Island. Unfortunately, Moira seems unable to help, and says that Xavier is "beyond the help of medical science". Beast considers contacting Lilandra of the Shi'ar, who would have advanced medical technology unavailable on Earth, although without Xavier they are not sure how to do this.
Meanwhile, on Genosha, the attack on Xavier (who is "as normal as mutants get") sparks fury and many mutants start preparing for war with humanity. They clamor for Magneto to lead them. Mutant uprisings begin all over the world, even taking total control of some cities. Morph takes on Xavier's form in a televised broadcast calling for an end to the violence, although it has little effect. The X-Men realize that they will have to attack Magneto directly on Genosha to have any hope of stopping Xavier's dream from falling apart. Since thousands of mutants have gone to Genosha ahead of them, they deem it a suicide mission, but Cyclops, Jean and Wolverine go anyway.
As they approach Genosha, Magneto uses his powers to destroy the Blackbird. The three passengers jettison, and survive the fall thanks to Jean's powers. The break into Magneto's fortress while he is giving a speech to his followers. They fight him and seem to be losing, but Magneto suddenly stops when he discovers that Xavier's televised message was fake and that Xavier himself is dying. Jean realizes that Magneto could use his powers to augment Xavier's powers and contact Lilandra. Magneto is hesitant, since it will mean giving up the army at his command and the chance to change the world that he has been waiting his life for, but he eventually agrees because of the love he has for Xavier.
Back at the mansion, Magneto uses his powers to help Xavier send a psychic message. Xavier regains consciousness and says goodbye to each of his X-Men separately. He says he is proud of them all, then seems to pass away. Lilandra arrives, and says that Shi'ar technology can extend Xavier's life, but only while he is under their care. She takes Xavier away, but with one last telepathic message, he promises that his spirit will always be with his X-Men.
- This was the final episode of X-Men: The Animated Series to air.
- While Henry Gyrich gives his talk about mutants and the dangers they pose, he mentions specific incidents from previous episodes of the series: "Come The Apocalypse", "Sanctuary, Part 2", and "Red Dawn".
- Sunfire comments that the X-Men have "been to this island before", referring to the events of "Slave Island".
- Trish Tilby was a reporter friendly with Beast in the original "X-Factor".
- As Trish Tilby reports on events, the symbol on the news van behind her is apparently that of J3 Communications, the broadcasting company owned by J. Jonah Jameson in the "Spider-Man" animated series.