Meet PC Donal Lynch; an insomniac and functioning alcoholic. Donal is new to working the beat in London, trying his best to forget one particular night. After all, there aren't many police officers who can say they have a convicted murderer for an ex-girlfriend. So when a woman is murdered on his patch, Donal knows this case can't go unsolved. But how do you solve a case with no leads? As his past demons catch up with him, what will crack first, the case or Donal?