Spider-Man learns that the Green Goblin is planning to travel across the multiverse using the Siege Perilous he stole from S.H.I.E.L.D. and the energy of Electro, to collect the DNA of other Spider-Men. Spider-Man follows his enemy to the futuristic (and CGI-animated) world of Marvel 2099, and helps boost the confidence of Spider-Man 2099. Then he travels to a gender-swapped universe and teams up with Spider-Girl to defeat their world's versions of the Goblin.