Astounding Stories #28

Xavier has tracked down Lucifer, who cost him the use of his legs, but finds his foe's heartbeat is rigged to a giant thermal bomb. The X-Men arrive in Bavaria and run across the Avengers who have also just arrived. The X-Men have to stop the Avengers from defeating Lucifer since by defeating Lucifer, the world will be destroyed. After Xavier gives Lucifer a mind blast that renders him unconscious, he contacts his team for help and the Avengers agree to let the X-Men clean up the current crisis on their own. Cyclops uses his eye beams to disable Lucifer's thermal bomb.