The New Mutants find Jamie Madrox within a locked vault underground. They bring him back to the X-Men, where Beast examines Madrox. He admits being a duplicate of "Jamie Madrox Prime," and Hank informs him that he is deteriorating. Soon after, this Madrox steals Bishop's time travel device, and things get weirder.
Multiple Man #1 has an interesting enough start. The New Mutants being an active part of X-Men continuity again is cool, even if it may just be because Matthew Rosenberg writes both. The idea of the only surviving Multiple Man being a duplicate instead of the original opens itself up to some intriguing potential about the nature of identity — yes that sounds a little pretentious, but it would be neat to see that explored.
There is still potential for that to be a coming theme in the miniseries, but the back half of the story doesn't fill me with hope. Things over-the-top bizarre, and the plot implodes into a stringy mess. It's the "we're going to throw a bunch of sudden twists at you, and you just have to trust us to explain it later" storytelling method that's not uncommon in comic books.
If they were genuinely interesting twists, this wouldn't be a problem. However, these are the kind of twists that you know are going to be hyper-convoluted and don't really care to see explained.
The artwork of Andy MacDonald does provide a nice visual identity to the comic, adding a bit of grit while keeping things comic book-y and light. It does lead to some characters being visually simplified like Bishop, for better or worse. Tamra Bonvillain is the color artist, and her work is bright, well balanced, and appealing.
Multiple Man #1 is a bit of a disappointment. I'm a fan of Jamie Madrox and was eager to see more material focusing on the character, but this seems a little too zany and off-the-wall for its own good. I wouldn't have a problem with a lighthearted and funny Madrox tale, but this just looks like it will quickly become a convoluted mess as shown by the ending. It's not outright bad, but I can't recommend it either.