Miles Morales, along with a team of Spider-People, must protect the multiverse when they clash on how to handle a new threat, redefining what it means to be a hero.

Taking place right after the events of Spider-Man: Across the Spider-Verse, Gwen Stacy leads the newly reformed Spider-Gang in a race against the Spider-Society, led by Miguel O'Hara, to find Miles Morales, who is trapped in the home dimension of the spider that bit him, along with an alternate version of himself as the Prowler, while the Spot begins his deadly attack in his dimension with far-reaching multiversal consequences.

When teenager Miles Morales gets bitten by a radioactive spider, he becomes the new Spider-Man in his dimension. However, he soon discovers that there are other versions of Spider-Man from alternate dimensions. Miles must team up with these different versions, including Peter Parker, Gwen Stacy, Spider-Man Noir, Spider-Ham, and Peni Parker, to stop the villainous Kingpin from opening portals to other dimensions and destroying New York City. Along the way, Miles learns what it truly means to be a hero.