A gambler is found dead, and it is discovered that he had thousands of pounds stashed in his flat, leading the team to suspect that he was part of an illegal betting scam. The wife of the owner then gets killed out riding and the investigation heats up further. Meanwhile, Burke is convinced that a former heroin addict and petty criminal has changed, until he is left with a decision to either arrest a killer or do a deal to catch a more major criminal.