While on leave, the soldiers visit a prostitute named Rowena. Wykowski spends thirty minutes with her, while Selridge's visit lasts only a minute. Carney chooses to remain loyal to his girlfriend. Eugene, feeling anxious, talks with Rowena and eventually loses his virginity to her.

Meanwhile, back at the barracks, the other soldiers find Eugene's journal and start reading it aloud. They uncover Eugene's candid opinions about them: he believes Carney can't be trusted, notes that Selridge calls out for his mother in his sleep, and describes Wykowski as "pure animal but likely to win a Medal of Honor." When Eugene returns, they hide the fact that they have his journal, though he soon notices it's missing. Wykowski then begins to read from it. Eventually, Arnold gets hold of the journal, and despite Eugene's pleas, he reads it. Arnold discovers that Eugene respects him but is uncomfortable with the suspicion that Arnold might be gay.

Later, Toomey barges into the barracks in the dead of night, waking everyone up. He announces that two soldiers were caught in a sexual act in the latrine, but one managed to escape through a window. Toomey demands the guilty party to confess, and when no one does, he suspends all base privileges and weekend leave. The soldiers suspect Arnold was involved, and Eugene starts to realize the impact of his words. The next morning, Toomey reveals the other man's identity, James Hennesey, who now faces up to five years in military prison.

Shortly after, Eugene embarks on a mission to find someone to fall in love with. At a USO dance, he meets Daisy, a student at a local Catholic school, and is smitten. Eugene tells her he plans to write to her.
Back at camp, Toomey is drinking heavily because he is being transferred to the Veterans Hospital the next day. He calls Arnold over and expresses his desire to shape him into a disciplined soldier. Toomey points a loaded gun at Arnold, forcing him to take it away. He then instructs Arnold to summon the platoon to witness Toomey being charged with threatening an enlisted man. Toomey seems intent on being reported, but accepts Arnold's offer to drop the charges in exchange for Toomey doing two hundred push-ups.

The following day, a man described by Eugene as rational, sensible, and respectable takes over Toomey's position. Eugene continues to correspond with and visit Daisy. On their final date before he departs overseas, he confesses his love for her and kisses her for the first time. As the play concludes, the soldiers are once again on a train, discussing Hennesey, who received only three months in prison and will then face a dishonorable discharge. At the play's end, Eugene reveals the outcomes of his fellow soldiers to the audience: Selridge was promoted to sergeant and trained new recruits in Biloxi; Wykowski lost a leg in combat but was recognized for his exceptional bravery; Carney was hospitalized for severe depression after enduring six months of enemy attacks; Arnold was declared missing in action; and Daisy married a Jewish doctor. As for Eugene, he injured his back on his first day in England and spent the rest of the war working as a reporter for the army's publication, Stars and Stripes.