It’s the end of an era, with Marvel announcing the end of writer Jason Aaron’s time with the Earth’s Mightiest Heroes — an end that involves a crossover between his two Avengers series, fittingly titled 'Avengers Assemble!'

The storyline, which begins in the Avengers Assemble: Alpha one shot in November, will spill over into both Avengers and Avengers Forever the following month, as all Avengers across the multiverse are forced to reckon with the biggest threat they’ve ever had to face — one that threads through not just Aaron’s run so far, but the very history of humanity itself, and across multiple Earths!

“Four years of Avengers stories. Threads from really every major series I've worked on throughout my last decade and a half at Marvel, from Ghost Rider to Thor. It all leads to this. The biggest Avengers story I could possibly imagine,” Aaron said in a statement provided by the publisher. “Featuring a cavalcade of characters from across creation. And I'm so deeply thrilled and honored that it all kicks off with an oversized Alpha issue that's being drawn by the legendary Bryan Hitch, who I'm getting to work with here for the very first time. Avengers Assemble. Say the words like a prayer. It's the only thing that can save you.”

Beyond Hitch, who’s illustrating the Avengers Assemble: Alpha issue, Aaron is working with artists Javier Garrón and Aaron Kuder on the story.

The first issues of the regular series to be included in the crossover are Avengers #63, in which the heroes team up with the Avengers of 1,000,000 BC to prevent the Multiversal Masters of Evil from destroying all Marvel history as we know it, and Avengers Forever #12, where assembled heroes from across the multiverse fight to defend Avengers Tower at Infinity’s End from Mephisto and his army of ne’er-do-wells.

More information about the storyline, and Aaron’s final Avengers issues, will be released in the weeks to come, according to Marvel.

Marvel’s teased this event before; back at San Diego Comic-Con they teased the title and promised that it would be the biggest Avengers story to date.