After returning from an intense three day training session, Private Tracy Walters crashes into an oncoming car, killing one civilian and injuring another.
A journalist attached to the Derbyshires disappears. It is then discovered that she used fake documents to get in with the unit. McDonaugh begins to think she may be a terrorist.
McDonagh and Roper are called in to investigate a woman who staggered on to the weapons range in a distressed state. They learn she is Capt. Emily Garnett who claims she was kidnapped by a man she met online and who then held prisoner.
10k of drugs are discovered and Pte. McKewan is missing. Kripo tell Jo and Hippie that he works for sex trafficker Turgut Ata. Burns and Vickery get caught up in a bank raid. Burns is shot but realises one of the raiders is Sgt. Hamon.