A gang of career criminals plots the robbery of an armored car company's headquarters. Although the robbery itself goes off as planned, it's not long before the gang members are fighting among themselves over everybody's share of the loot and trying to avoid capture by the police, who are pouring all their resources into capturing the robbers. Based on a real-life 1950 Brinks Armored Car Co. robbery in Boston.

À Boston, Chips McCann, patron d'une boîte de nuit, forme un commando afin de braquer un fourgon blindé transportant un magot de 2 millions de dollars. Il confie l'opération à Red Mack, attendant alors la sortie de prison de son vieil ami Pop Kane. Quand ce dernier est enfin libéré, les préparatifs du coup débutent et durent plusieurs semaines. Le braquage se déroule à merveille, les voyous portant des masques d'Halloween...