- Directors: Allan Dwan
- Producers: Edmund Grainger
- Writers: Harry Brown, James Edward Grant
- Genres: Action, Drama, War, Romance
- Actors: John Wayne, John Agar, Forrest Tucker, Adele Mara
Tough-as-nails career Marine Sergeant John Stryker (John Wayne) is greatly disliked by the men of his squad, particularly the combat replacements, for the rigorous training he puts them through. He is especially despised by Private Peter Conway (John Agar), the arrogant, college-educated son of an officer Stryker served under and admired, and Private Al Thomas (Forrest Tucker), who blames him for his demotion.
When Stryker leads his squad in the invasion of Tarawa, the men begin to appreciate his methods, except Conway, who considers him brutal and unfeeling when he apparently abandons a wounded comrade to the enemy. During the battle, Thomas goofs off when he goes to get ammunition for two comrades, stopping to savor a cup of coffee. As a result, he returns too late – the two Marines, now out of ammunition, are overrun; Hellenpolis is killed, Bass badly wounded. When Stryker discovers the truth, he forces Thomas into a fistfight. This is seen by a passing officer, but Thomas unexpectedly gets Stryker out of trouble for hitting a subordinate by claiming that he was being taught judo. His conscience ravaging him, Thomas breaks down and abjectly apologizes for his dereliction.
Stryker shows his soft side while on leave in Honolulu. He picks up a bargirl and goes to her apartment. He becomes suspicious when he hears somebody in the next room, but when he investigates, all he finds is a hungry baby boy she is supporting the best way she can. He gives the girl (the widow of a marine) all his money and leaves.
Stryker’s squad fights in the battle for Iwo Jima, witnessing the iconic flag raising on Mount Suribachi. (The flag used was the actual one raised on Mount Suribachi after the battle. It was loaned by the US Marine Corps Museum in Quantico, Virginia.) Afterwards, while the men are resting during a lull in the fighting, Stryker is killed by a sniper. His men find a letter on him, addressed to his son, saying all the things he wanted to say, but never got around to.