The X-Men are travelling on a ship across the North Atlantic. Scott strains himself when he blasts a huge iceberg in the path of the ship. As the rest of the X-Men tend to their leader, Scott explains that Xavier had a mission for them in Europe. Just then, Scott is mentally contacted by Xavier. The latter tells Scott that he has found Lucifer and is going after him.
Apart from the X-Men, the Avengers also find themselves in Bavaria. The Avengers encounter a tourist, who is frightened off by them. The tourist speeds off in his car and knocks into the X-Men (who appear human and normal compared to the Avengers) and starts babbling about what he had seen. Angel immediately flies off to check it out.
Meanwhile, Xavier discovers that Lucifer has built a bomb, synchronised with his heartbeat. The bomb would go off if he were to die, leaving Xavier in a dilemma. He projects his mental energy to summon his X-Men to him as Lucifer sends an “ionic ray” at the X-Men.
The X-Men escape the blast thanks to the warnings of Xavier and change into their X-Men uniforms. They soon come face to face with the Avengers. Thor claims that his hammer has led him to “the evil” which they assume are the X-Men. The X-Men battle the Avengers above ground as Xavier tries to stop Lucifer underground.
With great finesse, Xavier manages to render Lucifer unconscious while keeping his heart rate constant. Xavier then contacts Thor and explains that the X-Men fighting off the Avengers was just a ruse to prevent them from accidentally harming Lucifer and setting off the bomb. With everything cleared up, the Avengers leave peacefully.
Xavier then directs the X-Men underground to assist with defusing the bomb. With precision, Xavier instructs Cyclops to defuse the bomb. Having saved the earth from harm, Xavier sets Lucifer free.
(X-Men: The Early Years #9 is a reprint of Uncanny X-Men (Vol 1) #9.)