Marvel is taking readers back to the very start of one of their most iconic franchises. This December will mark the 60th anniversary of the X-Men, and to mark the occasion the publisher has announced a new, super-sized one-shot featuring the original five members of the team that will also set up stories to come next year. Original X-Men #1 will be written by Christos Gage and illustrated by Greg LandRyan Stegman provides the main cover for the one-shot.

Here’s how Marvel describes Original X-Men #1:

THE OG 5 ON AN ALL-NEW ADVENTURE!

Cyclops, Marvel Girl, Beast, Iceman and Angel – the first and greatest heroes to bear the X-Men name – once traveled into their own futures and reset the course of history. Now another multiversal mystery calls them forth. When the dust settles, one hero will remain, trapped in the world as we know it. With shocking surprise guests and heart-pounding twists and turns, Christos Gage and Greg Land kick off a story that will shake the whole MU!

In an interview accompanying the announcement, Gage elaborated further on what the original X-Men will be facing in this one-shot:

Essentially, the original X-Men are plucked from their era by an older Jean Grey, a.k.a. Phoenix, from a different timeline. This is a middle-aged Jean Grey who wasn’t replaced by the Phoenix Force; instead, she found a way to coexist peacefully with it. But now she’s become aware of a deadly danger on another Earth in the multiverse… a problem even the Phoenix can’t solve. Only the original X-Men can. Why? Because the problem IS them. On this world, the original X-Men grew up and took over the world, amassing tremendous power… so much that they’ll soon be turning their attention to other realities.

Old Lady Phoenix chose these particular original X-Men because they have already been to their future and met their adult selves (in the All-New X-Men series that began in 2012) so they have some experience with this sort of thing. It’s up to them to find a way to either convince their older selves that they’re making a horrible mistake or somehow defeat these far more powerful versions of them. Basically, it’s about your younger, idealistic self coming into conflict with your older, jaded self who’s made compromises and given up dreams in order to survive and do what they think is best, even if that means making hard choices along the way.

Look for Original X-Men #1 to arrive in stores and digitally on Wednesday, December 20th.