David Collins comes back from the War with new ideas about the old established certainties of class and culture. As the austerity of the forties gives way to the boom of the fifties, he grasps his opportunities and within a decade has left his drawing office in a Birmingham factory for a director's office in a London advertising agency. Only his wife, Mary, a girl who yearns for a comfortable, ordinary marriage, is uneasy. But David is an honourable man -- he could never leave her. Until, that is, he meets Sally . . .