When a decomposed body is found hidden in the wall of an old factory building, Sam Ryan concludes he was murdered. He is eventually identified by his ex-girlfriend Selina Thomson as Marcus Saul, who had simply disappeared one day some seven years earlier. There has also been a break-in on campus and drugs have been stolen. The Dean asks Leo Dalton to speak to some of the students on the issue, but he's not quite sure what he can do.

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.