The real-life story of Dublin folk hero and criminal Martin Cahill, who pulled off two daring robberies in Ireland with his team, but attracted unwanted attention from the police, the I.R.A., the U.V.F., and members of his own team.

When a courier at the D-Day Courier Service mistakenly finds a pile of money in his regular delivery, he does some digging only to discover that the messenger company is a front for a drug ring. A reformed drug user himself, he sets out to crack the lethal ring.