The film opens with the on screen paragraph 'this film is based on actual events that took place in a Central European country not many years ago'. Yeah, course it is. During the credits we see a yet unknown nun in confession. Then we are introduced to Sister Gertrude (Anita Ekberg) who works in a hospital with a Dr. Poirett (Massimo Serato) and her roommate and friend Sister Mathieu (Paola Morra), other people work there obviously but these are the only ones you need concern yourself with at this point. Sister Gertrude has recently undergone surgery to remove a brain tumour and has been experiencing headaches, black outs and a loss of control. Dr. Poirett says that he thinks she is suffering from post operative shock and the symptoms that she describes are purely psychosomatic. In actual fact Sister Gertrude has become addicted to morphine. Sister Gertrude receives no support from her Mother Suerior (Alida Valli) as she tells Sister Gertrude that "it's a nun's vocation to suffer". After Dr. Poirett refuses to prescribe her anymore morphine, Sister Gertrude steals a ring from a dead patient and pawns it in the city buying the drug with the proceeds. Sister Mathieu steals morphine for her as well from the hospital. The patients and Dr. Poirett begin to notice that Sister Gertrude's personality has begun to change, for the worse. One night Sister Gertrude notices that a patient named Josephine (Nerina Montagnani) has put her false teeth into her glass of water on the dining room table during dinner. Angry Sister Gertrude throws them on the floor and stamps on them. Later that night Josephine has a heart attack in her room and dies, this is when Sister Gertrude steals the ring. Soon after this incident Sister Gertrude senses Dr. Poirett is becoming suspicious and talks to the director (Daniele Dublino) of the hospital and convinces him to fire Dr. Poirett. Things become worse for Sister Gertrude as Father Janot is bludgeoned to death and thrown out of a high window to make it look like suicide. More deaths occur as the new Doctor, Patrick Roland (Joe Dallesandro) can't quite believe what is happening at the hospital and he too also starts to have his suspicions about Sister Gertrude. Is Sister Gertrude a drug-addicted killer? Since the hospital doesn't want a scandal they try and cover up the deaths as accidents but eventually the truth is revealed............ Co-written and directed by Giulio Berruti I really didn't think too much of this European exploitation film. The script by Berruti and Alberto Tarallo is quite slow at times and surprisingly shy's away from the stronger sleaze and exploitation elements you may expect from a Euro film from this period and of this type. A bit of nudity, a sequence where a female patient gives a man in a wheelchair a blow-job and has sex with him and a scene where a woman has needles stuck into her face is about it. The film is set almost entirely in the hospital and the fact that Ekberg plays a nun is totally irrelevant and not really used to it's full potential. There are not enough suspects on show either, I always felt that it was going to be one of only two potential killers and I was proved right. And the films title 'Killer Nun' tells you just about everything you need to know as well. The killers motives are never really made that clear and the way they are revealed at the end is one of the poorest and most unimaginative I've ever seen, the killers unmasking is better in an average Murder, She Wrote (1984-1996) episode! I just didn't care about anyone or anything in this film, and that's never a good thing. Quite well made on a certain level but there are so many more better films out there in this genre. Dull, unexciting and somewhat uninteresting. Not worth spending good money on that's for sure.