The Watcher starts this issue talking about Phoenix background - this only should be a warning that this issue is special for Marvel Universe.
The X-Men were transported from Earth last issue, and now find themselves on a Shi’ar ship in the presence of Lilandra, Araki and Gladiator. The X-Men are ordered by Lilandra to hand over Jean, as she is a threat to the whole universe. Gladiator tells everyone what the Phoenix had done to an entire world after destroying a star. Xavier challenges Lilandra to a duel for the life of Jean Grey. After Lilandra talks to her allies at this subject - the Supreme Intelligence from the Krees and Empress R'Kll from the Skrulls, she acept the challenge.
The X-Men have one night to rest before the battle of their lifes. Jean is alone at her room and thinks about what she had become and had done as Phoenix. While training Nightcrawler is questioning if he should help Jean or not, because what she had done to that planet and its people. He suddenly fells from the walls but is helped by Angel, who also has doubts about Jean. Wolverine is at his room thinking about the battle and that no matter what happens, he would choose Jean. Beast is in enjoying a bubble bath thinking about what Lilandra did, imposing Jean's death without even a trial. Colossus wakes up in his room thinking about Jean's love and Phoenix's hate, and that they are two different person and do not deserve the same destiny. Storm also wakes up thinking about Africa, her life with the X-Men and about Jean, who is almost a sister to her and she will defend to the death. And finally Cyclops is starring at Earth from a window and also thinking about his fate as X-Men leader and Jean's lover. Cyclops thinks he understands Lilandra's decision but he couldn't just give Jean away without a fight. Then Jean enters his room wearing her old Marvel Girl costume. They kiss and tell how much they love each other.
Later the X-Men and the Imperial Guard are teleported to the Blue Area of the moon where they will battle. The Krees and Skrulls say that they should have judges at the battle, and then the Kree Bel-Dann and the Skrull Raksor are sent to the Moon also.
Angel tries to fly over the camp battle but in a place with low gravity his wings are stronger and he almost fly of the moon, being helped by Storm. Cyclops devides the team in two and each group fight against some members of the Imperial Guard. Starbolt shoots fire at Cyclops, Jean, Nightcrawler and Angel's group, while Oracle, Manta and Smasher attack them. In another place, Warstar attack Colossus and Beast while Gladiator throws Storm and Wolverine away. Wolverine fells inside the Watcher domaisn and is banned from there. Storm is then attacked by Earthquake and defeated by Hussar. Oracle disoriented Angel and Smasher throws him to a tunnel and Nightcrawler jump after him. At the ground he encounters Manta, and she quickly defeats him. Wolverine is then attacked by Raksor in the shape of Storm, but he senses that something is wrong and attacks the skrull. Bel-Dann helps him and that starts a battle between the Kree and the Skrull. Colossus defeats C'cil but B'nee defeats Beast and Gladiator shows up to punches Colossus. After a huge battle between the two, Gladiator is the winner.
Cyclops and Jean are the last X-Men to remain. Cyclops is then taken down and this causes the Dark Phoenix to reemerge. Professor Xavier then realizes that the things have gone too far and that he has to save the Universe. He tells the X-Men to fight her and they do. After she became weakened, Colossus stops a punch that would have killed her and then Jean takes control one more time. Jean asks Cyclops to kill her, because she couldn't stop the Phoenix Force and that she is frightened but one part of her like that feeling of power. At the end she kills herself in front of Cyclops, unwilling to take the risk of ever harming another life again. The Recorder tries to understand why she had done that, and the Watcher tells him that she did because she was still human, the only race capable of self sacrifice. The Watcher also says that even the X-Men never realize, this is the greatest victory of their lives.
Cover used as a homage on, among others, Exiles vol.1 issue 4.