Paddy O'Brien commanded the column. He had been preparing for months. Through the spring, his men had trained in the manufacture and deployment of mines, because armoured cars were appearing more often on Cork roads and the IRA had to find a way to counter them. The convoys he intended to attack could swell from two Crossley tenders to six, from twenty men to forty, depending on the day. The site he chose lay about a mile from Rathcoole village. To the south of the road, an elevated bank gave natural cover, and a pine wood offered concealment from anyone scanning the verge. On 14 June he sent word to the battalions in Newmarket, Kanturk, Mallow, and Charleville, asking every available volunteer to make for Rathcoole. By the next day he had upwards of 140 men under his command, armed with rifles, shotguns, and a single Hotchkiss machine gun.

The first convoy came through at half past ten in the morning, exactly as expected, and the volunteers let it pass. They were waiting for the return trip in the evening, so the setting sun would cover their withdrawal. The second convoy arrived around 4:30 p.m.: three Crossley tenders led by an armoured Lancia, twenty-five Auxiliaries in all. O'Brien divided his column into ten sections. Eight took positions in the hill and pine wood overlooking the road; two more held the north side, blocking any retreat behind the stone walls. The volunteers held their fire until the fourth lorry reached the sixth mine, more than half a mile into the ambush zone. The detonation was muffled because the ground beneath the road was too soft, but the lorry was disabled, and that was enough to begin the engagement. The Lancia turned to assist and drove over another mine. For fifty minutes the fight roared back and forth across the road.

The Auxiliary commander on the road that day was William Edward Crossey. Realizing how badly he was outnumbered, he ordered one of his constables, Francis Scott, to run back to Millstreet for help. Scott set out under heavy fire, made it through, and reached the barracks at Mount Leader House. Reinforcements came at once, but the relief column ran into three felled trees blocking the road; some of the men continued on foot and arrived only after the engagement had ended. By then the IRA's ammunition was almost spent. Each volunteer had carried just forty rounds, and the firefight had been continuous. They disengaged along pre-planned lines of retreat. British reports later credited a passing aircraft with their withdrawal, though no republican account mentions a plane. Of the twenty-five Auxiliaries in the convoy, two were killed and fourteen wounded. The IRA suffered no casualties at all.

The next day, an IRA party returned to lift the mines that had not detonated. They found 1,350 rounds of ammunition left behind on the road - more than the men had carried into the fight. Paddy O'Brien later wrote that the ambush had achieved its purpose: it inflicted losses on the enemy and proved to his own men that a well-placed landmine could blunt a convoy. The Auxiliaries saw it differently. Crossey was decorated with the Constabulary Medal alongside Constable Scott, William Kay, and Henry W. T. George. Reprisals followed. On 24 June, about a thousand British troops swept the countryside around Rathcoole. That same day, volunteer Michael Dineen was arrested, tortured and killed. On 1 July, Bernard Moynihan was shot dead and Rathcoole wood was burned. Plans for an attack on Mount Leader House were drawn up but never carried out: the truce came on 11 July, and the war was over.

The road still runs from Banteer to Millstreet much as it did then, between low fields and remnants of the pine wood. There are no large memorials at the site, but local memory has not let it go: An Cosantoir, the Defence Forces magazine, has published accounts of the engagement, and the IRA witness statements lodged with the Bureau of Military History are public reading. The men who fired and the men who were fired upon have been dead for decades. What remains is the geography that shaped the day - the bank, the trees, the curve of the road - and the knowledge that on a long evening in June, a hundred and forty Cork volunteers and twenty-five Auxiliary policemen met one another along a mile of County Cork road, and not one of them was the same afterwards.