DS Brooks and DS Devlin are called to investigate an unusual crime, a man has been attacked and had his kidney surgically removed. The team are horrified to learn that the stolen organ has been trafficked into the NHS and it has been transplanted into a very wealthy patient. With the case handed over to the CPS, a conflict of interests is soon apparent and James Steel finds himself in charge of the CPS as George Castle steps down from his post and dons his defence wig one final time.

Ronnie agrees to help his old friend and partner, DS Jimmy Valentine in an undercover drug sting, but a gun is pulled and someone ends up dead. What appears to be a tragic mistake is then investigated by internal affairs, and DS Devlin fears Jimmy is not all he seems. As they push for the truth the spotlight turns on Ronnie and his dark past as a functioning alcoholic when a ten year old drug case was left with a large quantity of missing heroin. The evidence is stacking up and James and Alesha battle Valentine's barrister, Evelyn Wyndham to bring enough evidence to court, and Ronnie's the key... but Ronnie refuses to testify.