When Aisling Conroy's boyfriend Jack is found in the freezing black waters of the river Corrib, the police tell her it was suicide. A surgical resident, she throws herself into study and work, trying to forget - until Jack's sister Maude shows up. Maude suspects foul play, and she is determined to prove it.

Cormac Reilly is the detective assigned with the re-investigation of a seemingly accidental overdose 20 years ago - the overdose of Jack and Maude's drug and alcohol addled mother. Detective Reilly is under increasing pressure to charge Maude for murder when his colleague Danny uncovers a piece of evidence that will change everything ...

This unsettling small-town noir draws us deep into the dark heart of Ireland, where corruption, desperation and crime run rife. A gritty look at trust and betrayal where the written law isn't the only one, The Ruin asks who will protect you when the authorities can't - or won't.