As Long Marsh comes under the spotlight, life on the tense and paranoid C Wing is altered forever - and everyone is a suspect

With C Wing on lockdown, the prisoners' mental health reaches crisis point in an under-resourced and chaotic system. Meanwhile, Rose sees an opportunity, and Toby threatens to escalate his suspicions.

Leigh becomes increasingly isolated from her sceptical colleagues. A guilt-ridden Rose takes a chance to make amends. Toby's suspicions lead him to his own investigations.

Whatever secret Leigh is hiding lies within the forged information on her birth certificate - but whether she will cross the line between officer and criminal and hand it over to Governor Ray remains to be seen. With some of the wing's residents trying dangerous new ways to get high, a prisoner story exploring the radicalisation of a young mind leads Ali to remind Leigh how big a difference she and her team can make to the lives of the inmates - and just how badly she needs to stay on C Wing.

Supervising officer Leigh Henry comes under increased pressure to produce her birth certificate to secure the promotion she so desperately wants. The return of a troublesome old adversary on the wing is the last thing she needs, and her controversial strategy to help a prisoner who's being intimidated pits her against Gary, but could bring an unexpected solution to her problem. Meanwhile, with the help of her colleagues, probationer Rose starts to find her feet in this terrifying new world - though a tense encounter with a prisoner reminds her what's really at stake.

Leigh Henry is a career prison officer who lives for her job, but has lost faith in the system - so she circumvents the rules, doing whatever's necessary to help the prisoners in her care. But Leigh's position at Long Marsh is under threat - which doesn't bear thinking about, especially as she appears to be secretly living on the wing.