Fionn is accompanied by a shrewd solicitor, Mark O'Halloran, nicknamed "The Dry Cleaner" for his ability to scrub away the legal dirt of high-profile clients.
The series explores the corrosive effects of greed, the intersection of white-collar crime and international terrorism, and the technicalities of following the money trail.
In this episode, the , led by Detective Emer Berry, finds physical evidence—rough-cut diamonds—in the offices of wealthy businessman Fionn Brannigan .
Emer links these diamonds to recent bombings in Belgium. She warns Fionn that his involvement with dangerous figures has put his life at risk, famously telling him he "laid down with dogs and got up with more than [he] could handle".