After the fierce battle against the now-defeated Tabuu, several fighters were lost, transformed into trophies. Therefore, several of the survivors must explore a world filled with trophy-shaped prisoners to rescue the fallen. Along the way, multiversal chaos erupts with the arrival of people from other universes, such as Sonic, Mega Man, Pac-Man, and more, causing multiversal rifts that affect the multiverse. Thus, the Third Party gang (Sonic chose the name, obviously) must find a way to save the multiverse.
