Heroes Assemble MUSH is a superhero storytelling game that brings characters and worlds from DC, Marvel, and other properties together in a shared setting with its own canon and fixed timeline. Its fictional world places New York City, Gotham, and Metropolis along the East Coast, linked by HyperLoop rapid transit. The game aims for stories with the scale and atmosphere of a major superhero film or an established comic series.

Play is consent-based and collaborative, with players creating stories together rather than competing in tabletop-style combat. Players are welcome to run their own plots, while staff organize stories of varying scales. Participants can portray canon superheroes and villains, or introduce original superhero characters who may join existing groups or establish new ones. The site provides introductory guidance for new players, character and group lists, setting information, maps, plot resources, and an archive of roleplay scenes. A Discord community is also available, with invitations provided by staff.