The story shifts from the past to the present... the present Alison is a woman who has tried her best to leave her past behind. She moved to the Netherlands from Ireland ten years ago, desperate to escape public scrutiny and judgement. She never really did anything wrong, but when you're the ex of a serial killer... people talk. Ten years ago, she was just a young woman in love with a charming, handsome guy. She had no idea she was in love with a murderer.
Ten years later, it's beginning again. Young ladies are being stalked and drowned in the Grand Canal. Yet the Canal Killer, Will Hurley, has been locked up for the last decade. The similarities to the crimes cannot be ignored, and it isn't long before the authorities go to speak to Will. Clearly he hasn't been escaping during the night and committing these terrible crimes himself, but does he know who is? A former accomplice, an admirer? He refuses to speak to them, demanding to see his old love. Ali is the only one he'll talk to, and he insists he has a lot to say.
Ali reluctantly agrees to go back, but is understandably not thrilled at the prospect of dredging up the past and seeing her first (and only) love again.