While on a cruise to Europe, Cyclops is contacted by the Professor and informs him that he found Lucifer. Professor X tells Cyclops that was Lucifer who broke his legs in the past, and warns that Lucifer must never menace Earth again. Professor is on Lucifer’s trail and after avoiding a trap, is caught by the villain. Xavier shoots at Lucifer but is warned that if he is harmed, Earth will be doomed.
Elsewhere, the Avengers seem to be in search for some kind of disruption, some great evil that attracts Thor's hammer. Lucifer launches a thermal-bomb that will explode if he is killed. The Avengers follow the disruption and it leads to the X-Men. The two super hero teams battle; The Avengers want to destroy Lucifer and the X-Men know he must not be harmed. The Professor uses his telepathy to put Lucifer unconscious. Professor X then tells Thor that Lucifer is not a threat anymore and the two team stop their battle. Professor X then gathers his X-Men and they disable the bomb. Professor lets Lucifer go.
This is the first time the Avengers and the X-Men are put together.