The plan, as the IRA understood it, was simple. The unit would lure a Royal Ulster Constabulary patrol to a fixed point by detonating a small bomb near Drumrush Lodge, then ambush the responders. Earlier that morning, Fleming and Antoine Mac Giolla Bhrighde had stolen a Toyota van across the border in Pettigo, County Donegal. They loaded it with nine beer kegs, each holding about a hundred pounds of explosives, and drove the bomb through the country lanes into Kesh, where they met two more volunteers - Patrick Bramley and James Clarke. They did not know that the SAS was waiting. British intelligence had penetrated the operation; the ambushers were the ones about to be ambushed.

What happened next has never been fully agreed upon. Republican accounts hold that Mac Giolla Bhrighde, who was unarmed, was challenged, told the soldiers he had no gun, was shot in the side, handcuffed, and then shot dead. The Conflict Archive on the Internet records a gun battle in which Lance Corporal Alistair Slater, from the Parachute Regiment - though the SAS magazine Mars & Minerva later identified him as a member of 7 Troop, B Squadron, 22 SAS - was killed in the exchange. Two former SAS soldiers, Charles 'Nish' Bruce in his book Freefall and Andy McNab in Immediate Action, described a firefight in which both men died. The truth is somewhere in the field between the lodge and the river, and most of the people who could settle it are dead or sworn to silence.

What is certain is that the remaining IRA volunteers were trapped between the SAS positions and the river. Bramley and Clarke crossed somehow into the Republic, only to be arrested days later by Gardaí after trying to hijack a car near Pettigo. Fleming, who had been one of thirty-eight IRA prisoners who escaped the Maze Prison the previous September, went into the water. He drowned within minutes. His body was carried downstream and was not found until 21 December. At his funeral, severe rioting broke out between Republican mourners and the RUC. Four days after the Kesh ambush, on 6 December, his cousin William Fleming and Danny Doherty were shot dead by the SAS on the grounds of Gransha hospital in Derry. The Derry Brigade had lost four men in less than a week.

The site itself is unremarkable: a stretch of forested country at the edge of Lower Lough Erne, the kind of place where caravan parks, boat hire, and quiet roads make a perfectly ordinary corner of Fermanagh. The Bannagh River still feeds into the lough. Drumrush Lodge still operates as a restaurant. Two months before the ambush, the IRA had bombed the Grand Hotel in Brighton in an attempt to kill Margaret Thatcher; the famous statement that followed - 'today, we were unlucky, but remember, we only have to be lucky once - you will have to be lucky always' - hung over the entire conflict. At Kesh, the calculus reversed. The ambushers were ambushed, and three men died on a Sunday morning beside a winter river.