In France in 1944, American soldiers Berle, a deserter; Nick Colasanti, a petty thief; Fred, nicknamed "Assassin"; Tony, a mutineer; and Lieutenant Yeager (arrested for refusing to execute orders to kill, among others, women and children) are sentenced to death for their crimes and are shipped to a prisoners' camp near the Ardennes.
During the journey to the camp, the convoy stops because of a flat tire, and Fred and Berle are ordered to change it. Their work is interrupted by a Luftwaffe air raid. The five criminals take advantage of the attack and escape. Yeager takes command of the group and decides to find a way to neutral Switzerland.
On their way, they stop at an abandoned factory in the French countryside to rest and refill their supplies. While they eat, the upper floor of the building collapses, and a German soldier appears from between the hay bundles. Captured by Yeager's group, he tells them that he is in fact an escaped prisoner sentenced to death just like them. Although Tony and Fred want to kill him, Yeager prefers to take him along in case the Nazis attack again.
Later, the group runs into a German patrol, and the captured soldier proves very helpful. He convinces the patrol that the Americans are his prisoners, and they manage to kill part of the patrol and escape. After this, the group see a group of beautiful German nurses bathing naked in a river. Nick suggests the Americans pretend to be German soldiers, and they are able to get on friendly terms with the girls. However, after they see Fred, who is black, the nurses realize the men are Americans and start shooting at them. Tony, Nick, Berle and Fred run away to a nearby camp.
But the situation does not get any better. Some German soldiers arrive at the camp, and Yeager sends the captured soldier to talk to them. After discussing something with them, the German soldier realizes that the newly arrived are in fact Americans and shouts: "Americans! Americans!" The German soldiers kill him and Yeager's group return fire, killing the Germans. Yeager later learns he made a mistake from Colonel Buckner; the squad he shot at actually consisted of Americans dressed in Nazi uniform who were supposed to accomplish an important mission. At this point, the only solution is to trust the group led by Yeager with this task.
Meanwhile, Berle meets Nicole, a French nurse affiliated with the Resistance movement. He falls in love with her but it is Tony she is crazy about. Another problem arises as Fred and Buckner fall into the enemy's hands. Yeager, Tony, Berle and Nick attack the Nazi fortifications and free their friends. After the group is reunited, Colonel Buckner explains to them the plan, according to which they are to assault an armored train shipping a prototype of the V-2 missile.
According to the plan, the train is supposed to pass a mined bridge. But there are unexpected problems as Nick is unable to contact his comrades due to a broken transmitter, and is killed in an attempt to warn them. Berle is killed by the train driver, and when all hope seems to be lost, Lieutenant Yeager decides the outcome of the battle in a heroic act, in which he blows up the train with the missiles and himself on board, destroying the station assaulted by the Nazis.
Ultimately, the only ones to survive are Fred (who is wounded but escapes into the French fields), Colonel Buckner, and Tony, who manages to return to Nicole.