David Burke uncovers the clandestine activities of Patrick Crinnion, a Garda intelligence officer in the Republic of Ireland who secretly served the British Secret Service, MI6, during the initial years of the Troubles. At the same time, The Garda Sìochána believed they had an informant in the IRA's top ranks; upon discovering this was a carefully planned deception, they launched a major manhunt, with Crinnion himself playing a crucial part in the effort to arrest him. Before he disappeared, Patrick Crinnion's activities unravelled a web of secrets in Irish and British politics: the discovery of another British spy in the Irish police, Crinnion's damaging intelligence leaks and a cover-up concerning the murder of a garda. It exposes MI6's shady dealings, attempts to wrongfully implicate a politician in criminal activities and their plans to use criminals for assassinations. Additionally, the book reveals the secret surveillance of a key IRA member and Crinnion's entanglements with some of Ireland's top politicians. Through meticulous research, David Burke reveals the fate of Patrick Crinnion but also provides an insightful look into a period marked by covert operations, betrayal, and a power struggle that shaped modern Irish history.