July 1924. Diana Foster, five years old, is with her widowed mother, Emily, and the Fisher family, on New Brighton beach. Diana is spoilt and rather wilful, and despite Emily's warnings, Diana climbs out along a ridge of rock, slips on seaweed and plunges in to deep water. She is rescued by a neighbour's child, Charlie Fisher, and Diana conceives a violent passion for her rescuer, which he does everything in his power to avert. The Fosters and Fishers live in a court off Vauxhall Road and when Emily is found to have TB and is sent to a sanatorium in North Wales, Beryl Fisher agrees to take Diana in. Charlie is dismayed by this and he and Diana have many quarrels and then a terrific row, after which Diana swears never to speak to him again. Quite soon after the incident on the beach, a neighbour's son, Ian Carlisle, begins to take a great interest in Emily. Diana hates him and is violently jealous, so when her mother is sent to the sanatorium, she thinks that at least it will break up the relationship between Emily and Ian. This, however, is not the case; Ian continues to visit Emily in the sanatorium though Diana is unaware of it. But when Emily is allowed to return home, she is told that she must no longer live in the city or do a demanding job which calls for physical strength. Emily decides to move to a village in Wales and Diana realises, with dismay, that her whole life is about to change...