Starbug is attacked by an advanced Space Corps enforcement probe, for looting from derelict ships. The crew manage to escape by entering GELF space but Starbug crashes on a moon. Lister must marry the GELF chieftain's daughter in exchange for an oxygen breathing unit. The crew escape with the engine part during Lister's honeymoon, but the GELF chieftain sends his pet, a polymorph, after them to retrieve his new son-in-law.