Christopher Gill is a serial killer fixated on his late mother, a celebrated stage actress. He targets lonely middle-aged women, using his position as a Broadway theatre owner and director to slip into a range of disguises that put his victims at ease and keep his identity hidden: an Irish priest, a German plumber, a flamboyant gay hairdresser, a policeman, and a transvestite. Once he has earned their trust, he strangles them and then marks their foreheads with a garish red lipstick kiss, painting a haunting (and telling) signature on his victims.
Detective Morris Brummell is trailing the serial killer, quietly building a case as the murders unfold. He publicly describes the latest killing as carefully planned and executed, a description that seems to feed Gill’s inflated sense of genius and prompts him to begin taunting Brummell over the phone. For the most part, Brummell can only piece together small clues about his elusive foe, including the fixation on a mother, while Gill keeps the trail frustratingly clean.
Brummell’s personal life adds friction to the investigation. His overbearing mother, Mrs. Brummel, wants him to be more like his successful doctor brother and to settle down, while she disapproves of Brummell’s police career. Into this already delicate balance steps Kate Palmer, Kate Palmer, who enters Brummell’s life and wins over his mother by claiming she aims to become Jewish and by presenting herself as someone who can domineer her partner.
To draw Gill out into the open, Brummell fabricates a sixth murder victim for the newspapers. Gill, believing he has a copycat in play, phones Brummell and tries to pin the murder on a phantom killer; Brummell then engineers a moment in which Gill describes his own physical appearance in detail. When a false newspaper report claims a suspect has been arrested, Gill calls Brummell in relief, only to learn that the suspect has been released, angering him enough to escalate his target to Palmer.
Gill arrives at Palmer’s apartment in the disguise of a caterer, and the attempted attack is thwarted, forcing him to flee. During the ensuing police manhunt, Gill is spotted entering his theatre through a side door. Brummell, curious and cautious, chats with the man, unaware that he is Palmer’s attacker. A large portrait of a woman with deep red lipstick in the theatre lobby becomes a chilling clue when Gill reveals that the woman is his mother, unintentionally exposing his true identity.
As Brummell confronts the killer with his suspicions, Gill pretends to stay calm. Brummell heads toward the costume room, and on his way back past the stage, Gill launches a deadly attack with the backstage rigging. Brummell fights back and fatally shoots Gill before Gill can strike again. In his final moments, a deranged Gill imagines some of his victims in the audience and begs Brummell for forgiveness, before dying from his wound.
