The new Ultimate Universe Spiderman, thirteen-year-old Miles Morales, meets an adult Peter Parker Spiderman of the regular Marvel Universe--and Mysterio is the cause of it.
What makes this interesting is that the older Spiderman shows Miles what it means to carry on the tradition. For Peter Parker, it's a bit upsetting finding out that his alternate-universe self had recently died as a teenager . It's particularly weird when he goes to meet Aunt May and Gwen Stacy. May doesn't take this too well--but Gwen asks him how her other version is. He lies--and tells her that she's cool but older, like him. He asks if there's a Mary Jane and Gwen says yes. She doesn't believe her when he tells her that his MJ is a Supermodel.
Meanwhile, at the Triskelion, Tony Stark is working with Nick Fury about the alternate world and how to get there. Tony is obsessed about meeting another Iron Man. And the reason Nick Fury is letting the two Spider men run around and meet up with Peter Parker's family is that he feels guilty for failing the sixteen-year-old dead Peter Parker Spiderman.
In the end, the older Parker returns to his world with an appreciation of what Spiderman means, as does MIles in the Ultimate Universe. The last scene is of Parker looking on the internet to see if there's a Miles Morales in his world--and appears shocked when he finds out who he is. I'm sure, eventually, there will be a story about this.
I found this to be an interesting side-story to the current events happening in the Ultimate Universe timeline, particularly because I haven't picked up a regular Spidey comic in over a decade. Recommended.