On the night of August 6th, 1985, just outside of the picturesque village of Tolleshunt D’Arcy in Essex, England, a shocking attack left five members – and three generations – of a family brutally murdered. At first, the police thought they were dealing with an open-and-shut case, suspecting that it was Sheila Caffell – diagnosed with schizophrenia – who had shot her adoptive parents and twin sons before turning the gun on herself. As one detective set out to prove, however, certain elements of that narrative that didn’t add up – and the spotlight turned to Sheila’s brother, Jeremy...