1. Tracks

A car is left on a railway level crossing causing a catastrophic train crash which kills fifteen people, though the car driver cannot be found. DS Sam Casey struggles to cope after failing to save a young boy at the scene of the incident. This forces DS Ronnie Brooks and the recently promoted Wes Leyton, who is an old colleague of Ronnies and who is covering for DI Natalie Chandler, to keep a close eye on him. Initially the police suspect the car owner, the unpleasant Michael Gennis ( Adam James ), but learn that the car was stolen and the actual driver, Finn Tyler ( Aidan McArdle ), intended to kill himself by driving onto the track but changed his mind at the last minute.

Jake Thorne is anxious to prosecute him for murder but Tyler's defence barrister, Kate Barker, puts up a case of diminished responsibility by reason of suicidal intention. At trial Kate shows Tylers vulnerability and mental illness to the court and the jury agrees. Tyler is found not guilty of murder but guilty of manslaughter by reason of diminished responsibility. Meanwhile Jake's boss, CPS Director Henry Sharpe, springs one more surprise on the Chief Prosecutor, Kate as his junior assistant. But before Jake has time to protest, Kate excuses herself to check on Tyler. However down in the holding cells, Tyler is found dead and suspicion falls on his last known visitor, DS Sam Casey.