Writer: Stan Lee
Penciller: Jack Kirby
Inker: Chic Stone
Letterer: Sam Rosen
A beautiful day at sea is suddenly interrupted when an iceberg emerges from a fog bank. As the ocean liner barrels towards it, unable to maneuver out of the way, the crew braces themselves for the worst. Then by some miracle, the iceberg is destroyed, saving the ship, and all who sail aboard her. Of course, in reality it is no miracle, but the actions of an American teenager, Scott Summers, also known as Cyclops of The X-Men.
Unfortunately for Scott, the tremendous effort of destroying the iceberg with his optic blasts has overwhelmed him, and he is quickly rushed off, to be cared for by his fellow X-Men teammates. While the mutant heroes are caring for their acting leader, Professor X contacts the team telepathically. The Professor informs his students that he is currently deep underground, on the trail of Lucifer, the man who is responsible for the injury which left The Professor paralyzed. Xavier warns the teens that if something should happen to him, they must continue his work, and prevent Lucifer from causing any harm to the world. At this, The Professor is caught in an artificial dust devil, sent by Lucifer, who has been watching The Professor’s progress. The dust devil takes Xavier to Lucifer, where it solidifies and traps The Professor. In spite of his imprisonment, Xavier attacks, shooting at Lucifer, only to be warned that if any harm should come to Lucifer, the entire world would be in peril.
Nearby and above ground, The Avengers arrive in a small European town. The team has been following strange impulses being emitted by Thor’s hammer Mjolnir. The impulses indicate a great evil and have lead The Avengers to this town, little knowing that Lucifer lies beneath their feet. As they begin to determine their next course of action, an American tourist drives nearby. Knowing that the situation is likely to soon degrade, The Avengers encourage the lost tourist to quickly depart the area. The confused motorist eventually makes his departure, only to run smack into the X-Men. Relaying a description the bizarre people he just encountered (The Avengers), The X-Men take it on themselves to investigate the tourist’s claims.
Returning underground, Lucifer shows Xavier the inner workings of a massive nuclear weapon that Lucifer has in his possession. Judging correctly, Xavier is horrified to learn that Lucifer has connected the trigger for the bomb directly to his own heartbeat. If anything were to happen to Lucifer, then the bomb would detonate with enough force to destroy an entire continent. Additionally, knowing that Xavier’s lauded X-Men must be nearby, Lucifer sends a blast of ionic energy to eliminate the unsuspecting teens.
In his mental illusory state, Xavier is able to warn The X-Men in time, and they just barely avoid Lucifer’s attack. The team then suits up and begins to investigate the surrounding area in earnest, this time finding The Avengers. Although The Avengers initially offer to help The X-Men, Xavier warns the team to prevent The Avengers from reaching Lucifer, as any injury they may cause could be disastrous for the world. The situation escalates quickly and The X-Men soon find themselves fighting The Avengers.
While Lucifer is distracted watching the two teams of superheroes battle, Xavier uses his incredible telepathic abilities to incapacitate Lucifer, without damaging his heart. With the immediate threat neutralized, Xavier is able to contact Thor, the Avengers’ chairperson for the week, and explain to him the situation. With this knowledge, Thor convinces his fellow Avengers to end their assault and the team leaves The X-Men to complete their mission.
Once the team has joined their mentor, The X-Men quickly act to disable the bomb’s fuse. As The Professor locates their target, Lucifer’s heart begins to flutter, indicating that the bomb could go off any second. With only moments to spare, Cyclops is able to destroy the fuse, and thus save the world from total destruction. With the threat removed, Xavier wakes up Lucifer and allows him to go on his way, reminding his students that they have vowed to never harm a human being.