(Follows from the events of Fantastic Four #27)
In this issue, the X-Men use new uniforms, designed by Jean.
Simultaneously Professor X and Magneto hear media reports of a powerful mutant named Namor, the Sub-Mariner, who could be valuable to their cause. Both seek out the Submariner in their astral forms, but Magneto is the first to arrive. Magneto convinces one of Submariner's subordinates to convince the prince to go to Magneto and join him. Hoping stop this from happening the X-men board a boat to one of Magneto's secret island lairs.
The X-men arrive too late to prevent Submariner from meeting the Brotherhood. Magneto attacks the X-Men's boat with his powers amplified by a giant magnet he had built in the island. The X-men escappes and star to fight. The battle results in Quicksilver being restrained by the X-men. Magneto decides that Quicksilver is expendable and threatens the Scarlet Witch. Outrage by Magneto's treatment of the Scarlet Witch, the Submariner attack s Magneto and destroys the giant magnet. Professor X calls for an end to hostilities, the Brotherhood flee without Submariner and the X-men return home.