DI Lewis and DS Hathaway investigate the murder of Dean Greely. As the investigation continues, they discover that Greely and three other men had formed a club during their Oxford student days, the Sons of the Twice Born. Today, the men have little contact with one another and initially deny that their club existed. When a second member of the foursome is murdered, it becomes apparent the they have a secret, one from 30 years ago and that someone is out for revenge.