Episode spoilers.
John Basilone and his men move through Guadalcanal's jungle, where an unseen Japanese shooter kills their lieutenant. Their position offers little comfort: food is poor, supplies are short and everyone is dirty and tired. When Army stores arrive, Marines seize an opportunity to take food during an air raid. The brief relief ends with a naval bombardment that sends them into shelters and leaves the ground shaking around them through the night.
Chesty Puller prepares the Marines to defend the approaches to Henderson Field. Basilone's machine gunners face a heavy Japanese assault, and the defence begins to buckle at another position. He carries a hot gun across the battlefield to reinforce the threatened line, burning himself as he moves it. He keeps the weapons firing and gets ammunition where it is needed. By morning the attack has been stopped, but Manny Rodriguez is among the dead Basilone finds afterward.
Basilone cannot stop thinking about the small choices that might have changed his friend's route that night. Back in Alabama, Sledge tells his father he intends to enlist. His father's fear concerns what combat will do to his son as well as whether he will survive it. The exhausted Marines finally leave Guadalcanal aboard a Navy ship. Fresh coffee and the sailors' welcome surprise Leckie, whose unit learns that people at home have followed their ordeal and regard them as heroes.