Medical student Sam Waterhouse is convicted, solely on the basis of circumstantial evidence, of the gruesome murder of mother of six-year old Tess. Twenty years later, after his release a ten-year old girl and shortly thereafter a ten-year old boy are murdered in the same area. Sam Waterhouse immediately becomes the prime suspect. However, Inspector Jury, who has been assigned the case believes that there is a different connection between the present-day murders and the tragedy twenty years previously. The trail leads him and his aristocrat friend Melrose Plant to the noble Ashcroft family and their new governess Tess. Time is of the essence however, as there could soon be another victim.