A decades-old secret steeped in Marvel history will be told for the first time in September.

In the one-shot special Journey Into Mystery: The Birth of Krakoa, by writer Dennis Hopeless (Jean Grey) and artist Djibril Morissette-Phan (All-New Wolverine), Nick Fury and the Howling Commandos embark on one final top-secret mission in the closing days of World War II.

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Set years before Fury became the Marvel Universe's leading super-spy, the story follows the elite commando squad on a mission that leads them to cross paths with the living island Krakoa.

"Krakoa is a classic X-Men fixture — from its first appearance in Giant Size X-Men #1 to revelations about its true nature in X-Men: Deadly Genesis decades later, ‘the Island that Walks Like a Man’ has fascinated generations of readers … but we’ve never known the story of how it came to be — until now!" editor Annalise Bissa said in a statement. "In this story, we fill in some of the history of Sergeant Fury and his Howling Commandos as well. Their story drops off late in WWII and we don’t see the Howlies again until they’re reunited during the Korean War, after several years of civilian life. So…what did they do at the end of the War? And how does it intersect with the atomic origins of Krakoa?"

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Introduced in 1975 in Giant Size X-Men #1, by writer Len Wein and artist Dave Cockrum, Krakoa was presented initially as mutant in the form of an island that captured most of the classic X-Men team. To rescue his teammates, Cyclops recruited an all-new, all-different squad to venture to the mutant island, a creature borne from nuclear weapons testing. With atomic weapons playing such a pivotal role in the final days of World War II, the one-shot special will show how Fury and the Howling Commandos figure exactly into Krakoa's origins.

Journey Into Mystery: The Birth of Krakoa will be released Sept. 12 by Marvel.