When Cassie Swann is knocked off her bike on a quiet country road, the driver leaves her unconscious and bleeding at the roadside. A man later walks into a police station and confesses, and they gratefully close the case. But something about this guilt-induced confession doesn't smell right, and Cassie's relentless suitor Charlie Quartermain cannot resist doing a little detective work. When a young student at Oxford is found brutally murdered, Charlie begins to suspect that the two incidents are somehow connected. Can he save Cassie from another 'accident' - this time a fatal one?