Retirement does not seem to be suiting Lewis, so when a call comes from Innocent to take up his badge and rejoin the force, he doesn't hesitate. Elsewhere, Hathaway is wading into his first murder mystery. It began with an arson attack on a hunting lodge but soon enough Hathaway and DS Maddox have a dead neurosurgeon to deal with.

The team start to investigate the shocking murder of an American classics student called Rose Anderson whose body is discovered in the canal with stab wounds to the neck and abdomen.