Normandy, 1944, post-D-Day. A tank commander, Sgt. Joe Davis, is very popular with his men. So much so, that when he is killed during a brief skirmish with the enemy, his crew fall into despondency. That is, until Davis's replacement, Sgt. Sullivan, shows up. To the men, his arrival is like a splash of ice water. "Sully" rouses them out of their funk by ordering the immediate discard of Davis's personal effects. Further, he replaces their tank driver with a known drunkard named Tucker. Sully's anatagonism doesn't stop there. He challenges the loyalty of a German-American crew member named "Heinie." He verbally bullies another man, Kolowicz, into near-fisticuffs.
In short, Sully transforms a crew of emotional zombies, bemoaning their fate, into an over-achieving squad of efficient killers. All of this, despite their collective hatred of Sully. But in the following months, as they fight their way to the Siegfried Line, both Sullivan and the men begin to share a mutual respect.