On 26th May 1986, the body of an undercover British agent was found by the side of a muddy lane, with a rope tied around its wrists and tape over each eye. The brutal killing of Frank Hegarty began a decades-long search for justice. In a compulsive blend of investigative journalism and true crime thriller, Henry Hemming exposes the parallel worlds of the IRA and British intelligence through the lives of those inextricably bound up in both. After his recruitment by British secret intelligence, Frank Hegarty infiltrated IRA circles and became trusted with the most covert operations. But soon Frank would have to make an impossible decision, with devastating and deadly consequences. In 2016 a detective began to investigate the chilling possibility that Frank was murdered by another undercover British agent, known as 'Stakeknife'.