Muswell Perkins is bored. Life is too ordinary, with nothing to do but meet his friends in the cafe or to go swimming under the bridge. Two events change things. First he meets Rosie and her strange brother, who have parked their caravan near the quiet Fenland town. The second event is the arrival of a motorcycle gang who set up camp down by the river and receive late night visitors. Rosie is determined to find out exactly what is going on and enlists Muswell's help. Events move faster than they anticipate, and Muswell and his friends are suddenly in great danger.
Sally Robey's sequel to Tyso's Promise centres on a young Jamaican boy (his origins don't become apparent until late in the story) and a travelling Romany girl. Rosie and her brother Tyso are travellers, misunderstood and mistrusted by many people. The story serves to highlight the theme of people who do not fit the 'accepted norm'. The hostility of the motorcycle gang suddenly makes Muswell sharply aware for the first time of his Jamaican parentage and the efforts of his father to make him conform to what he sees as 'proper' behaviour. The author combines a dramatic story with keen observations of the uncertainties felt by many teenagers.