Two young girls are killed on railway by a passing train. It does not seem to fit the profile of a normal suicide. So if this is a double homicide who would do this and why? Martin Beck and his team start following the step backwards in order to figure out what has happened. With good and intensive police work they find man side trails from the main path.

Three students murdered at century-old boarding school. Killer drowned himself; body never found. On 100th anniversary of killings, student researching incident vanishes, along with others, as dark presence haunts school.