Uncanny X-Men #100

Aboard a space station in Earth orbit, the “all-new” X-Men (Banshee, Wolverine, Nightcrawler, Storm and Colossus) are confronted by what appears to be the original X-Men team (Cyclops, Iceman, Angel, Beast and Marvel Girl) who are being directed by Professor X to kill the new team. Havok and Polaris also appear and take sides with the original team. A battle ensues, but the members of the new team note some curious inconsistencies with those whom they are fighting: the original team have no memory of their replacements; the Beast isn't covered in blue fur; Cyclops is wearing his old visor; and Havok and Polaris don’t seem to recall Erik the Red.

Most of the new team fight on the defensive, concerned about injuring their friends and comrades whom they believe are being mind-controlled. Wolverine, however, attacks Professor X and is caught off-guard when the Professor stands on two legs and knocks him down with one punch. Marvel Girl then attacks Wolverine, who now suspects something fishy. Using his feral senses, he deduces the truth and stops pulling punches, savagely slicing Marvel Girl open with his claws. At first, his comrades are shocked that he would use lethal force on Jean, until they see that “Marvel Girl” was really a robot, a Sentinel masquerading as Jean Grey… as are all the others. Now knowing the truth, the new (real) X-Men quickly destroy the “X-Sentinels”.

Observing the battle from a secure location, Lang is enraged that his ruse has been exposed. To his captives (the real Jean Grey, Cyclops and Prof. X as well as Peter Corbeau), Lang rants that he created the X-Sentinels to be unbeatable duplicates of the original X-Men. He intended to have them seek out and exterminate all other mutants, which would advance his genocidal agenda while laying the blame for mass murder on the X-Men themselves. A flashback montage recounts how Lang discovered the late Larry Trask’s former base and used his notes to build a new line of Sentinels. His plans were funded by a shadowy organization called the Council of the Chosen, and he used the government-sanctioned Project: Armaggeddon as a front for his true goals.

While Lang rants, Cyclops uses the opportunity to optic-blast through his confinement and free Jean, the Professor and Corbeau. Cyclops attempts to knock out Lang, but he manages to flee to a gunship. Jean uses her telekinesis to prevent Lang’s escape and forces Lang's gunship to crash into a viewscreen and explode, seemingly killing Lang in the process.

The whole team is reunited, but find themselves stranded on the space station now that Lang's minions have used all the escape pods to flee, and the approaching solar flares will very likely kill everyone still aboard the station. Upon examining the shuttle, Corbeau determines they can use it to escape but that the autopilot has been damaged. Although the shuttle has a containment room that will shield its passengers from the solar flares, somebody will have to remain on the bridge and manually pilot the ship back to Earth… and whoever that pilot is will be incinerated by the solar flare’s radiation!

Jean volunteers for the suicide mission, stating that her telekinetic abilities can protect her from the radiation. She telepathically absorbs Corbeau's knowledge on how to pilot the shuttle, but all are aware that Jean will likely die. Scott balks, but she knocks him out and orders the other X-Men and Corbeau into the shielded room. Wolverine and Storm try to talk Jean out of sacrificing herself for them, but to no avail.

Sealing the hole in the ship with a telekinetic shield, Jean begins the dangerous task of piloting the ship back through Earth. In the shielded room, Cyclops revives and tries to break free, forcing the other X-Men to restrain him. As Jean flies the ship through the solar storm, her powers are pushed to the limits and the radiation pushes through causing her extreme pain. As she is overcome, she screams out Scott's name.