013: 'In The Know'

D.S. Max Carter is taking surveillance photos of Mark Wilson who is seen arguing with Josie Hibbert when he witnesses an off-duty P.C. Leon Taylor intervening. Back at the station, Max discusses the case with D.C. Grace Dasari and D.I. Neil Manson, who think they should investigate further before talking to Leon. The team soon uncover that Josie is a prison officer at Longmarsh where Shaun Wilson, Marks brother, is serving time for drug related offences.

As the investigation develops, the officers discover that Mark is forcing Shaun's girlfriend, Ria Crossley, to smuggle a phone into Longmarsh. Max follows Ria to Josie's house where she forces the phone into the prison officer's hand before leaving. The sergeant is shocked when a few minutes later, Leon also leaves the house…

At the station, Max confronts Leon about his involvement with Josie but the P.C. insists they're just friends and has no idea what the earlier altercations with Mark or Ria were about. Convinced that Josie is being forced to smuggle the phone into prison and aware that Shaun is planning a murder, Max tells Leon they need to bug the phone and persuade Josie to take it in.

Leon is reluctant, but meets Josie who explains this is the first time Mark has asked her to smuggle something in for Shaun. Although terrified of the Wilson brothers and what they could do to both her and her young son, she decides not to take the phone in. Desperate, Leon is forced to tell the truth and begs her to take the phone…

Max is furious that Leon has told Josie about the operation and convinced she will compromise the case, he visits her in prison. She admits to meeting up with Ria a couple of times outside of work after talking to her during one of Ria's prison visits: Ria saw her as someone she could confide in about her volatile relationship with Shaun. They're interrupted by an altercation in the prison visiting room where Shaun has attacked Ria.

Outside the prison, Max catches up with her and Ria explains she has just broken up with Shaun, who clearly didn't take it well. Max takes her back to the station where she admits Shaun was violent, jealous and controlling. Grace, concerned for Ria offers her a contact card and support before she leaves the station.

As the case continues, Max and Grace listen in on Shaun's phone calls to his brother and realise that he's planning a hit and Ria is the target…

Realising that Ria has gone to Josie's, armed officers flee to her house, with Leon following closely behind. As cars and police surround the house, Leon is horrified to hear two gun shots ring out. Mark eventually opens the front door and drops the gun before being quickly arrested, but are they too late…?