On a trip to Las Vegas, Kevin, Hamster and Gretel encounter the aliens that gave them their powers and learn that much more sinister things are happening.
Hamster and Gretel must face their worst fears after battling a supervillain who can materialize people's greatest fears. Kevin and Gretel's strict grandmother comes for a visit.
Gretel is jealous of the amount of attention Kevin has been giving to the family dog after he goes viral online. Kevin, Gretel and Hamster work to protect Bailey's birthday party from someone who has repeatedly ruined birthday parties.