 In London, the teenager Paul Grahame (John Howard Davies) lives with his upper class but financially broken family. His wasteful mother Hester Grahame (Valerie Hobson) is a compulsive buyer, spending all the family money in new expensive dresses, jewels and objects for their home. His father Richard Grahame (Hugh Sinclair) is a gambler, losing money in the horse races. His uncle Oscar Cresswell (Ronald Squire) is permanently covering the Grahame family debts. When the servant Bassett (John Mills) is hired, Paul finds that he can predict the winner of the horses  races rocking his wooden horse. Paul asks Bassett to become his partner, betting their money in the races, trying to prove that he is lucky and silencing the permanent whisper of the house needing more money. But the prize is high and fatal.