A mysterious package shatters a woman's seemingly perfect life, plunging her into a descent of fear and into the depths of a terrifying asylum. Lucille Morrow, a woman of beauty and devotion, vanishes after receiving an enigmatic delivery. Driven by overwhelming fear, she voluntarily commits herself to a psychiatric institution. Inspector Sands, tasked with uncovering the truth behind her disappearance, embarks on a grim investigation that leads him through a labyrinth of horror, murder, and a chilling quest for retribution.

Margaret Millar's 'The Iron Gates' is recognized for its masterful construction of suspense and its exploration of psychological darkness. Critics often highlight Millar's ability to weave intricate plots that delve into the darker aspects of human motivation and societal undercurrents. The novel is frequently praised for its atmospheric tension and its compelling portrayal of a protagonist driven to extreme measures by fear and circumstance. Readers often find the narrative's twists and turns to be both surprising and deeply unsettling, cementing its place as a notable work in the suspense genre.