An uninvited alien guest brings the worst out of the crew – then eats it. Feeding on the fear, anger, guilt and vanity of its prey, the shape-shifting “Polymorph” creates an even more dysfunctional adversary: their alter-egos. Unable to hatch a plan that doesn’t involve leaflet campaigns and kicks to the balls, the psychotic Lister, placard-waving Rimmer, boorish Kryten and drunken Cat must unite in order to survive, the face of the enemy changing at every turn.