1815. Peter and Paul Skillen, identical twins and fearless thief-catchers, stalk all who dare to walk in the shadow of the hangman. When they catch a notorious burglar, they claim a handsome reward and infuriate the Bow Street Runners who believe they have a monopoly on policing in the capital. Home Secretary Viscount Sidmouth faces a crisis. During a massacre of American prisoners-of-war at Dartmoor, two escape and come to London in search of retribution – and if their demands are not met, they’ll kill Sidmouth. The Runners compete fiercely with the twin detectives to bring the villains to justice in a compelling tale of murder, kidnap, revenge and political machination.