Passion Killer is a story of how unrequited love, jealously and obession become dangerous, turning passion to murder. It revolves around a group of friends in a small town in Ireland. Sylvia arrives home one evening to find her boyfriend in a pool of blood. In the course of their investigation, Detectives Barbra Molloy and Mick Naughton question the group of friends and uncover a web of deception. A party the night before the murder left many fingerprints at the scene of the crime. In the tangle of love triangles there are plenty of motives to choose from and few alibis, casting the net of suspicion wide.

As the story unfolds, the friends discover secrets and lies that test their relationships to the point of breaking.