Set in Dublin (a rather surprising giallo setting), Iguana opens audaciously with an acid-throwing, razor-wielding maniac brutally slaying a woman in her own home. The victim's mangled corpse is discovered in a limousine owned by Swiss Ambassador Sobiesky (Anton Diffring, Where Eagles Dare) and a police investigation is launched, but when the murdering continues and the ambassador claims diplomatic immunity, tough ex-cop John Norton (Luigi Pistilli, A Bay of Blood) is brought in to find the killer…