The police may have a serial killer on their hands when they locate a second body in a site where the first victim was found several months before. The body was trussed up in the same way and had an identical burn mark on his back. There is no apparent link between the first victim, student Michael Haughty, and the second Jason Villers, a probationer at the police college. While the police find evidence that may solve the Otty case, they have nothing on the Villers murder. In a separate case, Harry is approached by the wife of an old university friend who asks him to perform a post-mortem on her husband who died in a fall. Harry finds that his old friend was injecting himself regularly. Leo's family is visiting for a few days but he's constantly being called into work.

When a second police probationer dies at the police college, Sam concludes that they may be dealing with a copycat murder rather than a serial killer. The investigating officer thinks that a fellow probationer may have been responsible for the original murder but the college's commandant, whose son is a student there and soon to be a police constable, would like the reputation of the college protected and the whole thing swept under the carpet. Harry learns that his late friend's wife was prescribing the drugs he was taking and is not quite sure what to do with the information. Leo's relationship with his wife and daughter is stretched thin when he spends most of his time at work and they are left on their own.

El equipo acude al aparente suicidio del estudiante Jason Renfrew en la universidad local. El decano le cuenta a Leo que Jason se quejó con ella sobre acoso racista y se descubre que había ingerido un chip que contenía fotos de los presuntos acosadores, además de tener una pistola en su casillero. Poco después, un tirador comienza a matar a varias personas, incluyendo al policía que investigaba la muerte de Jason. Nikki y Harry quedan atrapados en un aula con algunos estudiantes, uno de los cuales, Matt Frisk, gravemente herido, fue uno de los acosadores de Jason. El comandante Somerville lidera al equipo de policía que los libera, aunque es Harry quien encuentra al tirador gravemente herido. Sin embargo, no logra detectar la bomba que fue colocada en el campus.

Harry sospecha que Scott Weston, el pistolero herido, fue disparado por otra persona y se vuelve evidente que se usaron dos armas en la masacre. La madre de Scott le dice a Dean Mears que Scott y Jason eran buenos amigos, y que Scott cuidaba del más frágil Jason. Mientras tanto, Nikki es mantenida prisionera en la morgue abandonada por Neil Corrigan, desequilibrado, quien parece haber planeado la masacre junto con Jason, quien se echó para atrás y se suicidó, y luego culparon a Scott. Finalmente, las pruebas en video revelan lo que realmente sucedió, así como la ubicación de la bomba.