Written by Len Wein with artwork by Dave Cockrum, "Second Genesis" chronicles the story of Professor Xavier recruiting a new team of X-Men from around the world (consisting of Colossus, Storm, Nightcrawler, Thunderbird, Wolverine, Sunfire and Banshee) in an attempt to rescue many of his original team of students who have gone missing on the mysterious island of Krakoa.
Once united, Professor X presents many of the new mutant recruits with their first uniforms and, with the help of Scott Summers aka Cyclops (who was the only member of the team to escape Krakoa), sends the newly-formed team of mutant heroes to the island in search of his lost X-Men. When arriving on Krakoa, they break off into teams, face several dangerous obstacles and collectively reach a mysterious temple where they believe the X-Men are being held.
Once inside, they discover the missing mutants, who appear to be "attached" to the island itself by vines. They realize that the island is literally feeding off of the mutant captives, and when they are released, it becomes apparent that the island Krakoa itself is actually a large mutant monster that mutated everything on the island into a collective organism due to atomic bomb testing decades prior. A large battle ensues, but the X-Men succeed in escaping from the island, and defeat Krakoa by removing the creature from Earth and sending it into deep space.
Giant-Size X-Men #1 is the first appearance of Storm, Colossus, Nightcrawler and Thunderbird and is the first time readers have seen Wolverine since his debut in Incredible Hulk #180-182. This line-up of "All-New, All-Different" X-Men will continue and become the team's core members starting with Uncanny X-Men #94...in which writer Chris Claremont will begin his 16-year run as writer of the X-Men and the Uncanny X-Men title will go on to be one of Marvel's most successful comic titles for the next 2 decades.