When a beloved former colleague is assaulted by a mystery assailant and comes to him for help, Lennox quickly becomes embroiled in a new case.

With the discovery of another body, Lennox's suspicions that he is dealing with a serial attacker are confirmed when the perpetrator makes contact with him.

The chase is on as the killer plays cat and mouse with Lennox and Drummond and claims there will be another victim.

The case continues to evade Lennox when he discovers that there is a connection between the victims.

As Lennox wrestles with the consequences of his actions, the hunt to catch the killer ramps up when one of his own team is targeted.

Lennox makes a shocking discovery that turns the case on its head.