In the chaotic remains after the Police Club bombing, over the grim task of sorting through the pieces, Ian and Jock are forced to work together. With the death toll mounting, the only leads come from within the police force itself. One is the shell shocked young constable who is Jock's only eye witness. The other is a disgruntled policeman who may well have set off the bomb. The police find themselves doing what they dread most, investigating one of their own.

With the forensic evidence largely tagged and ready, Carol becomes increasingly cut off from Ian and the lab. Now that she has returned to work - abandoning her maternity leave - her entry into the team rearranges alliances at a critical moment. Other crimes are drawing much needed resources from the investigation. Jock takes too long to discover his team is close to disintegrating.