A wealthy young man named Tony moves into a lavish London townhouse and hires Barrett as his manservant to help him settle in. At first, Barrett appears highly competent, attending to Tony’s needs with meticulous care. However, as their relationship evolves, Barrett gradually wields influence over Tony's life, subtly undermining his authority. Barrett’s presence introduces a degree of dependency that begins to blur the boundaries between master and servant. This dynamic becomes further complicated when Susan, Tony's fiancée, expresses distaste for Barrett, sensing something amiss. Tensions rise as Susan’s suspicions grow, while Barrett seizes every opportunity to insinuate himself further into Tony’s daily routine.

As Barrett gains more control, he introduces his alluring girlfriend Vera into the household under the guise of needing a maid. Vera’s presence adds another layer of complexity to the household dynamic, as her flirtations and manipulations begin to sow distrust and confusion. The delicate balance of power shifts as both Tony’s personal and professional life start unraveling under the weight of Barrett and Vera's cunning strategies. The atmosphere becomes increasingly claustrophobic as Tony’s sense of self crumbles, caught in the web spun by those he once trusted. Secrets are revealed, personas manipulated, and intentions obscured, leading to a tense climax that challenges the notions of loyalty, control, and identity.