This low budget British entry in the oversubscribed serial killer stakes is rooted in a suburban tawdriness that passes for realism (Firth's balding babyface dentist is a plausible cellmate for Nilsen or Christie), but is stuck with a plotline of such wild silliness that it neither gets a grip as a psychological drama nor makes any sense as a mystery.
Crime writer Ellen Carter (Robinson) has got away with the murder of her abusive husband and despite the occasional intrusion of a persistent copper (Henderson), has settled down to normal life. Mysterious dentist Leslie Steckler (Firth) rents a room in Ellen's house and takes about five minutes to work out where hubby's corpse is bricked up, whereupon he reveals that he is the White Angel, an active serial murderer, who wants her to write a book explaining why he has a compulsion to kill blondes who dress in white. She agrees, but immediately starts scheming to get out from under his control and win back the normality for which she has already killed once. This takes some care with its characters but absolutely none with their actions.
The contrast between a one-time murderess and a habitual killer is potentially interesting, but Ellen never develops a professional interest in Leslie's crimes, so we never feel she has any complicity. There are too many red herrings (Leslie dresses as a woman for no other reason than that's the sort of thing movie murderers do and Ellen needs to borrow his blonde wig for a plot twist near the end) and it winds up with a hokey series of contrivances that would collapse like a house of cards if films like this had any logic