Robert Belstrang, ex-magistrate bored with country life, comes to London to investigate the strange disappearance of Thomas Jessop, son of a poor Catholic neighbour. He locates the youth in Bedlam asylum, silent and starving himself. When he tries to free Jessop, he is warned off the case by a politic lawyer, Anstis. Soon after, Belstrang finds himself drugged, robbed and falsely imprisoned.
Once released Belstrang persists in his investigation, but he is thwarted at every turn: unseen forces are at work who seemingly want Thomas Jessop to die. When Belstrang confronts Anstis, even he turns up dead.
The trail grows murkier by the hour, drawing Belstrang into the fear-ridden Catholic underworld – until he uncovers a plan with its roots in the Gunpowder Plot of more than a decade ago. Young Thomas, an embittered papist, was being used in a desperate scheme to mark the anniversary of the Plot. The scheme failed – and now the conspirators seem eager to cover up the whole business.
But Belstrang’s a stubborn man. With the help of ex-soldier Daniel Oldrigg, he sticks doggedly to his purpose – and stumbles on the real causes of the Anniversary Plot, which stem from the very heart of a corrupt government.
Belstrang must uncover the truth, or die trying.