- Captain America
- Giant Man
- Iron Man
- Crew of unnamed freighter
- Matilda & Samuel, a couple on cruise-ship
- Unnamed tourist in Bavaria
- Unnamed Bavarians
In the Northern Atlantic a freighter is on a collision course with an iceberg. Suddenly two red beams of light shoot out from the front of the ship and destroy the iceberg. Scott Summers and the rest of the X-Men head back to their cabin before anyone can see where the strange light came from. The X-Men attend to Scott who became weary after having to use his powers so rigorously. Scott then explains to the other X-Men that Professor Xavier had told him to come to Europe. Suddenly another transmission from Professor Xavier comes in telling his students that he has located his foe, Lucifer in a cave in the Balkans. He tells the X-Men that he wants them to come to the cave so that if he is unable to stop Lucifer, then they can finish him off instead. Professor Xavier begins to make his way into the cave, but is engulfed by a cyclone that places him right in front of Lucifer. Professor Xavier pulls a gun on Lucifer, but learns that if he pulled the trigger the world would be doomed. The X-Men arrive in a Bavarian Village where they are met by the Avengers. The Avengers inform them that they are there investigating strange vibrations in the ground detected by Thor's hammer. Lucifer reveals to Professor Xavier that he has built a thermal detonator attached to his heartbeat so that if he were harmed or killed, it would blow up causing worldwide damage. Lucifer knows that the X-Men have arrived in Europe so he fires an ionic ray at them. Professor Xavier is able to warn his students of the incoming ray so that they are able to dodge it. The X-Men are told of Lucifer's bomb and that Lucifer cannot be harmed. The Avengers arrive at the cave, but refuse to listen to the X-Men's explanation of why Lucifer cannot be harmed. A battle between the two groups ensues. Lucifer begins to laugh after seeing the two groups fighting each other. Professor Xavier uses the distraction to his advantage by knocking Lucifer unconscious without changing his heartbeat. Professor Xavier alerts Thor as to what has been happening. Thor informs the rest of the Avengers of Lucifer's defeat, so they depart. Professor Xavier leads the X-Men to his location so that they can defuse the bomb. Professor Xavier uses his powers to detect the bomb's weak point and orders Cyclops to use his power full force but in a hairline beam on the weak spot. The bomb is diffused just before Lucifer wakes up. Lucifer tells them that it took him 10 years to make the bomb. Professor Xavier says that he lost the permanent use of his legs, but Lucifer only suffered a minor setback, then the X-Men leave Lucifer alone in his cave.
Written by: Stan Lee
Drawn by: Jack Kirby
Inked by: Chic Stone
Lettered by: Sam Rosen.
- In X-Men #1, Professor Xavier says that he lost the use of his legs in a childhood accident. The full origin of how Professor Xavier lost the use of his legs is given in X-Men #20.
- This issue features a full-page pin-up of Jean Grey. Artwork by Jack Kirby, Chic Stone, Art Simek and Sam Rosen.
- The issue states that Professor X is located underneath the Balkan Mountains. Then the story takes place in a Bavarian village and says the Professor is below them in the mountainside, presumably the Bavarian Alps. These are two different locations. Bavaria located in Germany and Bulgaria in the Balkans.