In the aftermath of the Japanese attack on Pearl Harbor, Marine Sgt. John Basilone prepares to ship out; budding journalist Robert Leckie enlists in the Marine Corps; Sidney Phillips leaves for boot camp; the 1st Marine Division lands on Guadalcanal.
Basilone and the 7th Marines arrive on Guadalcanal to reinforce the 1st Marine Division as they defend a crucial airstrip; Basilone suffers a personal loss; the exhausted members of the 1st Marine Division are evacuated.