Andy Koehler begins his letter to his ex-wife, Phoebe, by recounting the weeks leading up to the moment he discovered her unfaithfulness. Phoebe leaves Andy and her son, Raymond, in Idaho while she and their daughters go to Tacoma so she can work at a dressmaking shop. She runs her business out of their friends’, the Newcomers, cleaning shop and stays with another of their friends, the Brocks. Meanwhile, her two daughters go to boarding school. In his letter, Andy laments all the signs of Phoebe’s affair that he missed, from her family’s history of infidelity to his friends’ warnings for him to keep an eye on her. At the time, he simply assumed she enjoyed parties and nightlife. He recounts how they said goodbye to each other at Pacific City so she could go to Tacoma. He notices she looks at him guiltily, but doesn't think much of it. After returning to the mine where he works, Andy writes many letters to Phoebe, but almost none receive a response. When a response finally arrives, Phoebe bluntly states she is busy.

Andy details the scandal Phoebe’s sister finds herself in after her husband punches her in the eye. After the incident is resolved, Andy decides to drive his car to Tacoma and see Phoebe, unable to wait so long for such meager responses. When he arrives, Phoebe is distressed that he didn't notify her of his visit. She explains that she has been living at the Newcomers’ house instead of the Brocks’, and when they arrive at the house, Mr. Newcomer tells Andy that if he had come later he might not have a wife at all. Andy is confused, but his attention is soon drawn to Phoebe’s illness. Three days prior, she fell into a horrible pain and a doctor was called to treat her. Looking back on his visit to his wife, Andy writes to Phoebe that he knows the Newcomers tried to help her end her promiscuity but failed. He knows she told them that she wanted to divorce Andy and marry her new lover. The Newcomers even contacted Andy’s brother to take Phoebe away from Tacoma, but she stayed, thus attracting many men to the Newcomers’ shop. In his letter, Andy asks Phoebe why she didn’t simply come to him to ask for a divorce. It would have left both of them in better places. He describes the abhorrence with which the boarding school’s owner, a typically kind woman, regards him when he and Phoebe pick up their daughters in Tacoma. That night, Phoebe also drags him to a party in the woods. Although all the other guests—including a group whose arrival Phoebe is very excited for—drink moonshine, Andy doesn't. He instead watches Phoebe begin dancing with one of the members of the group she was waiting for. Then he sleeps in one of the guest’s nearby houses. After being half-woken up by Phoebe returning with someone else, Andy wakes up fully at the rowdiness of the partiers in the shack next door. He goes outside, then realizes a couple is having an intimate moment in his car. Despite the man vanishing quickly after the couple finishes, Andy follows the woman until he discovers it is his wife. Immediately, he flies into a crestfallen rage, oscillating between hatred of every man at the party and regret for not keeping his wife closer.

The next day, as the two are leaving the city from the Bealor Hotel, Andy’s thoughts are filled with both hatred and love for Phoebe. After he sees her flirting with a truck driver—one of her paramours—in the hotel, Andy resolves to prevent Phoebe from dancing with him. He believes he married a girl too weak to overcome her desires and who needs to be watched over. Eventually, Andy forbids Phoebe from attending any dances, leading to many fights about Andy’s need for rest to work in the mine conflicting with Phoebe’s want of excitement. Later on, Phoebe moves out of Andy’s cabin and into a shack farther down the road so she can receive letters from her lover in Tacoma. She uses her flirtatious skills to sell silk socks to the men of the mine. Her lover is a worker at the same silk company.

After being evicted from their home, Phoebe serves Andy divorce papers. The divorce depletes Andy of almost all his money, but he writes to Phoebe that he still loves her and only wants to find her lover in Tacoma and bring him retribution. When he returns to a barbershop to retrieve his coat at night, a car almost hits him. Out of the car appears Brock, one of Phoebe's lovers. Andy writes that he knows Phoebe once told Brock to never reveal their relationship to Andy, lest he kill him. He then writes to Phoebe that she knows the rest of the story, then ends his letter.