It follows the adventures of an idealistic mad scientist named Dr. Niles, along with his team of outcast superheroes, each of whom suffered ostracism and alienation due to their supernatural powers.
After the events of season one, Niles, Jane, Cliff, Rita, Vic, and Dorothy still exist in miniature sizes, and Dorothy tries to befriend both Cliff and Jane.
The team embarks on new adventures after being freed from a wax prison. However, the atmosphere turns to dark horror with the appearance of a mysterious alien killer, who kidnaps the team to the afterlife, forcing them to confront their fears to save themselves.
In the fourth season, the team faces a catastrophic invasion of the undead and is forced to travel back in time to their teenage years to confront evil forces that threaten the universe.