Many years after the end of the war, Jimmy Cross visits Tim O'Brien at O'Brien's house in Massachusetts. They reminisce, drinking coffee and looking at old photographs of their Company. When they see a photo of Ted Lavender, Jimmy mentions that he's never forgiven himself for Lavender's death. O'Brien responds that he feels that way himself about other things. They switch from coffee to gin, and focus on less grim stories.
Cross and O'Brien's meeting shows how unbreakable the bond is of fighting together. Cross' guilt hasn't dissolved with the years—the self-blame will always haunt him. O'Brien mentions feeling the same way to foreshadow his own story of guilt. They switch to gin is to make the conversation regarding painful memories more bearable.
Eventually, O'Brien feels like the mood has lightened enough for him to ask about Martha. Cross stands up and returns with a picture of Martha playing volleyball. Cross asks if O'Brien remembers the picture, and O'Brien says he thought Cross had burned it. Cross says that Martha gave him a new one at their college reunion in 1979 after he told her he still loved her.
O'Brien remembers Martha after all this time to ask after her. Cross' response with a picture alludes to the strength of these memories. The photograph allows Cross to tell the story of seeing Martha again after the war.
At the reunion, Cross learned that Martha had become a Lutheran missionary and a nurse who had done service in Ethiopia, Guatemala, and Mexico. They took a long walk across campus. She had never been married and didn't think she ever would be.
The fact that Martha never married opens up the possibility that she did love Cross and he never came for her, or she simply defies conventional norms. Martha also went to foreign lands, but not for war. She went to help others.
Cross tells Martha that he loves her, but she keeps walking and doesn't answer. He walks her back to her dormitory and recalls how he had taken her back to the same spot after they kissed on their date before the war. He tells her about how, on that night, he wished he had taken her upstairs and tied her up so that he could touch her knee all night long. She closes her eyes and acts cold, and says she doesn't understand how men can do the things they do.
Their reunion is a close parallel to the date Cross reminisced about throughout the war, but it shows how much the war has changed each of them. His confession doesn't lead to anything between them; it only reveals their distance. Martha blames the atrocities of the world on the actions of men.
They have breakfast the next morning and she apologizes. She gave him another copy of the volleyball picture and told him not to burn it this time.
Martha gives him another picture because she still wants to be remembered, and perhaps because she wants to help Cross recapture his former innocence.
Cross tells Tim O'Brien that he still loves Martha. O'Brien tries to keep the conversation away from Martha for the rest of Cross's stay, but as he's walking Cross to his car O'Brien mentions that he wants to write a story about Cross and Martha.
The story O'Brien wants to write is "The Things They Carried." He makes it clear that that story is a war story, written by a writer—a war story to capture the war.
Cross thinks it over for a moment, then agrees to let O'Brien write the story, saying that maybe Martha will read it and come back to him. He makes O'Brien promise to depict him as a "good guy" who is "brave," "handsome," and "the best platoon leader ever."
Cross' list of things O'Brien must include in the story show how he still feels the weight of obligation. It is still important to him to look like an ideal soldier, to Martha and to the world.
Cross then makes O'Brien promise not to mention anything about something, but O'Brien cuts him off, promising he won't.
This could be in reference to any number of things, but so much of war is unspeakable and Martha won't understand.