When an undercover drug buy goes wrong, DS Ronnie Brooks finds himself in a very difficult spot. Brooks and DS Jimmy Valentine are posing as drug dealers when Valentine shoots the dealer claiming the man pulled a gun on him. Brooks was behind their car at the time and saw nothing but has known Valentine for many years and has no reason to doubt him. DS Matt Devlin on the other hand did not see the dead man pull a gun or do anything threatening and is given 24 hours by DI Natalie Chandler to find evidence or shut up. When the Crown Prosecution Service charges Valentine, the dirty cop testifies that Brooks was in on a drug theft. Ronnie has to call on an old friend to testify on his behalf but at a great cost to herself.