Annette Somerville, a young single mother, earns her living in a high-class Glasgow sauna parlour, scrupulously keeping her respectable home life separate from her professional activities. During a series of murders in the city, seemingly unconnected, Annette realises that all of the victims have been regular customers.

What should Annette do? No one else seems interested, and her boss makes it clear that going to the police will cost Annette her job. But Annette's new boyfriend, a former customer of the sauna, could be the murderer's next victim.

Can Annette continue to keep her two lives separate, or are they destined to violently clash?