When her father remarries only one year after the death of her mother, Kirsty Newton tries to accept her new stepmother Lois, and to be affectionate and helpful toward her, but finds herself increasingly overcome by feelings of intense rage and sorrow. Bitterly resentful that Lois has achieved an emotional closeness with her undemonstrative father, something she herself has always longed for, and painfully reminded of her loss every time Lois speaks, Kirsty's efforts to suppress her feelings and behave decently lead to a frightening series of anxiety attacks.

When Kirsty is given the opportunity to go away for the summer, to stay on a farm in Norfolk and pick fruit, she jumps at the chance to escape her problems. Settling into her new routine at Old Manor Farm with the friendly and down-to-earth Dillons, Kirsty soon befriends Jake Meryon, the local doctor's son, and becomes caught up in a mystery involving a strange whistling ghost.