On 9 July 1857, Angus MacPhee, a labourer from Liniclate on the island of Benbecula, murdered his father, mother and aunt. At trial in Inverness he was found to be criminally insane and confined in the Criminal Lunatic Department of Perth Prison.

Some years later, Angus's older brother Malcolm recounts the events leading up to the murders while trying to keep a grip on his own sanity. Malcolm is living in isolation, ostracised by the community and haunted by this gruesome episode in his past.

From Graeme Macrae Burnet, the Booker-shortlisted author of His Bloody Project, comes a dark, psychological thriller, leavened by moments of black humour and absurdity.