C.I. O'Donnell is summoned to a hearing conducted by Sir Robert Frey appointed by the Home Office to investigate corruption and betrayal in Special Branch in Northern Ireland. In particular the ethical conduct of undercover operations. While as Paddy Coil, his undercover name, working out of a Waterford law firm, O'Donnell understands the fine line between the letter of the law and covert operations in reality. Under the official secrets act and the rules of counter espionage he needs to tread carefully not to fall foul of political intrigue. Investigators from MI5 descend on the Waterford office (as well as those in other parts of the Island such as Dublin, Belfast and Londonderry. Then in a private session with Sir Robert he is asked to spy on his own people. How will he navigate the tricky business of spying on the spies? Meantime, IRA commander Toombs - needs to protect his sources in MI5 and Special Branch - this enquiry and investigation could mean more exposure than he would like. Time to cut the heard and make disappear the ones that have stopped being useful? O'Donnell gets caught up in the murder of colleagues that seem to be dropping like flies in the wake of his own investigations for Sir Robert!