In 1936, Millie confronts Alice at the library, accusing her of sabotaging the Montana guidebook notes. Alice admits to the sabotage and leads Millie to the town cemetery, stopping at Mac’s grave.

Alice explains that Professor Lyon had stumbled on a local story about Colette Durand, still alive and running a library near Seeley Lake—information Lyon had gathered from an interview with Red Fox, who had even given him a picture of her. Lyon planned to include the story in the guidebook. Fearing that the ambitious Finn Benson would use the guidebook to locate and harm Colette, Alice and Sidney intercepted the notes before they were sent to the project’s headquarters in Helena. They replaced the information about Colette with blank forms and nonsensical text. Alice insists their only goal was to buy Colette enough time to disappear again. When Millie notes that Colette is widely believed to have died years earlier, Alice smiles, confirming that this was the lie she successfully helped spread.

In 1936, Colette is living in a remote cabin in Condon, Montana. At a local saloon, she learns that writers from the Federal Writers’ Project recently visited and spoke to a local musician named Red Fox. Fox confirms that he told one of the writers, a professor, about Colette and her informal library service. Disturbed, Colette asks him to tell anyone who asks that she died years ago.

Three days later, Sidney Walker arrives at her cabin, warning her that her name and location were in the professor’s notes. He admits he did not read them until it was too late, and that a mystery writer on staff may have already skimmed them. Before he leaves, Colette gives him his forgotten camera and the film still inside it, which she has kept without ever developing. Believing a confrontation is inevitable, Colette decides to act first. She mails a note to Finn Benson with a single sentence meant to lure him to her: “I found it.”

Back in Missoula, Millie and Alice discuss Finn Benson’s motives. Millie argues that Benson’s past as a Company spy wouldn’t harm his current anti-union political campaign. Millie then produces Katherine’s telegram ordering all FWP materials to be routed through Senator Walsh’s office; she concludes that Benson must be behind it, since he works there. They deduce that Claude Durand must have discovered a secret even more damaging than Benson’s status as a spy: that Benson was stealing money from the Anaconda Copper Mining Company.

Millie theorizes that Benson likely also murdered Alice’s father, Clark Monroe, to eliminate the only other person who knew of the theft, and Alice works through the logic with her. They realize that Colette must possess the evidence her father found, without knowing what it is. Determined to help, Alice packs a bag. Millie picks her up and insists they bring Sidney Walker, as he is also involved. The three of them then drive together toward Colette’s cabin on Bluebird Pond.

Colette waits with a shotgun on her porch as Finn Benson’s car approaches her cabin. He arrives alone, arrogant and confident. She leads him inside, where she orders him to surrender his pistol and sit in a chair she has placed in the center of the room. When he mocks her resolve, she proves her seriousness by firing a warning shot into the wall just over his shoulder. As she holds him at gunpoint, ready to end their long conflict, the cabin door bursts open. Alice Monroe stands in the doorway, followed by Millie and Sidney.

Alice quickly explains their theory that Finn Benson was embezzling from the Company, which is why he has been hunting Colette. As Colette prepares to shoot Finn, Alice steps directly in front of the shotgun, pleading with her not to seek a revenge that would destroy her. She quotes a line from Hamlet, “The croaking raven doth bellow for revenge” (405) as a shared code between them, invoking their earlier understanding that revenge ended in tragedy for the play’s characters.

Their conversation leads them to suspect the evidence is hidden within one of Claude Durand’s books. Colette remembers her father quoting Shakespeare’s As You Like It shortly before he was killed. Millie asks Colette for a knife, takes the produced blade, and carefully pries open the thick inner paper from the back cover of the volume. Inside, she finds two hidden papers: An original and a doctored balance sheet, proving Finn stole $5,000 from the Company. As they realize the truth, Finn grabs Alice, holding a dagger to her throat and demanding they hand over the papers.

While Finn Benson holds Alice hostage, Millie quietly moves to the edge of his peripheral vision. To create an opening, Colette distracts Finn by asking him why he pretended to love her years ago. As he focuses on taunting Colette, Millie silently signals her plan to Sidney with a head-incline toward a nearby book.

To further distract Finn, Colette lets out a piercing scream. The momentary shock allows Alice to push Finn’s knife hand away from her throat. Seizing the opportunity, Millie grabs a heavy book from a nearby stack and swings it, striking Finn hard on the side of the head. He collapses to the floor, unconscious. Sidney immediately rushes forward to secure him with the shotgun. As the danger subsides, Colette laughs, revealing that the book Millie used as a weapon was The Complete Works of William Shakespeare.

In 1937, Millie receives a letter from Katherine. The letter confirms that the Montana guidebook will be published and approves Millie’s proposal for a new project: a book series titled “Women of Montana.” As she shares the good news, her friend Flo reveals a surprise: She, Oscar, and Tommy have already typed up the entire manuscript. Flo notes that Sidney told her he thought about helping, which she sarcastically presents as a monumental character shift for him.

Soon after, the first copies of the published Montana guide arrive at the FWP office. The small staff celebrates with whiskey, and Millie gives an emotional speech. She declares that the project’s true purpose is to introduce Americans to each other through their stories, arguing that the nation will always be stronger together.

By 1939, Colette is living a peaceful life at her cabin. After the evidence of his crimes was made public, Finn Benson was found dead in a motel from an apparent suicide. No longer needing to hide, Colette has started her own bookmobile, delivering books to residents in Condon and the surrounding towns. She maintains friendships through letters with Alice, Millie, and Roarke O’Callahan, a former hired gun who helped her years ago. Having found community and purpose, Colette visits a stone marker she created for her father. She decides that of all the labels she has carried, the one that fits her best is a word Alice once used to describe her father: shanachie—a Gaelic word meaning a keeper and teller of stories.

In 1936, the day after the confrontation at Colette’s cabin, Sidney leaves a copy of Louisa May Alcott’s Little Women on Alice’s porch. Inside is a photograph he took of her on the boxcar roof years ago and a passage underlined, encouraging her to live her life. As she prepares to leave Missoula for good, she finds Sidney waiting with a car, asking to be her “cocaptain.” They spend the next five years traveling the country together.

During World War II, Sidney serves overseas as a photographer, while Alice volunteers for the Victory Book Campaign, a project supplying books to soldiers. They reunite after the war and eventually return home to Montana. The narrative then flashes forward many years. Alice, now 93, is dying during a fierce blizzard. With her last strength, she retrieves her copy of Little Women and Sidney’s photograph of her sitting atop the Boxcar Library. Sitting by the fire as she passes away, she is content that she has lived a full life.