[Followingadvicefromhertherapist, ayoungwomanandherhusbandtrytospiceuptheirflaggingmarriagebytakingpartinsomekinkybondagegames.Meanwhile, thewoman'ssister, acop, ishotonthetrailofaserialkillerwithapenchantforblindfoldsandhandcuffs.Couldthetwoberelated?]！