What do you do when money laundering, blackmail, death, and a troublesome face from the past surface, and you're a stranger in the city?

Belfast is a city with a history for Sian O’Neill, so when she is sent there on a business trip, all she wants is to get in, get out, and keep it simple.
Instead she finds evidence of money laundering in the books of her client, Provincial Bank, and witnesses her teenage sweetheart roughing up a suspect during an arrest. This pales into insignificance though, when the manager of the team dedicated to preventing money laundering at Provincial is found dead. Sian finds herself accused of killing her, and only hours after she is interrogated, wakes up in casualty – the victim of a hit and run.
What is at the bottom of the quagmire in Provincial?