Sam must investigate a case with a painful personal connection when a close friend is murdered after the Cambridge May Ball.

A young woman is found dead in an empty house. Why was she there? Sam suspects another person was involved.

A tragic scene is discovered when a young mother apparently dies of an overdose. When another addict dies in an explosion, Sam has a bigger case on her hands.

The death of a farmer involving a combine harvester seems like an accident - until Sam receives an anonymous tip-off.