An American gangster nicknamed "English Joe" has fled across the Mexican border with his gang, consisting of four men in addition to himself. The American police are after them because of a bank robbery in which they killed several of the bank's employees. But "English Joe" soon comes up with a new plan that can bring them to safety for a while and at the same time give them the opportunity for a new coup. An old engineer who has worked at a weapons factory in Mexico has traveled home to his own country to complete an epoch-making invention: the silent machine gun. The men are ordered to Denmark, where the old engineer now lives.