Dr. Simon Sparrow's (Sir Dirk Bogarde) love life improves dramatically when lovely Delia Mallory (Samantha Eggar) is brought into casualty with a sprained ankle. As a model she's relieved at the diagnosis, and she's as attracted to Sparrow as he is to her. Meanwhile, Sparrow finds himself treating Sir Lancelot Spratt (James Robertson Justice), who has started sleep-walking. He has also suddenly lost his gruff manner, and is being nice to everyone. Sparrow quickly diagnoses Spratt's condition: he's fallen in love. The object of his affection is Physiotherapist Iris Merchant (Barbara Murray). Sparrow urges him on, but she has another suitor: Major Tommy Ffrench (Donald Houston). Spratt tries to hire a private detective to follow her, but when that doesn't work out, he follows her himself.