Set against the backdrop of Depression-era Montana, the novel interweaves three women's stories across two decades, connecting them through a converted train car that brought books to isolated mining and lumber camps.
In 1936 Washington, DC, Millie Lang is a young Texan working as an editor for the Federal Writers' Project (FWP), a New Deal program employing destitute writers to produce the American Guide Series, state-by-state travel books designed to "introduce America to Americans." When she punches the son of a powerful senator for assaulting a secretary, Katherine Kellock, a high-ranking FWP executive, saves Millie's job but presents a stark choice: transfer to Missoula, Montana, as the field editor for the state guide, or be fired. Katherine suspects that the Missoula staff's submission of blank forms and incomprehensible essays is sabotage by Montana's powerful Copper Kings, the mining magnates who dominate the state. Millie accepts, knowing failure means everyone loses their jobs.
The narrative shifts to 1924 Missoula, where Alice Monroe, the mayor's sheltered nineteen-year-old daughter and one of the town's librarians, conceives the idea of a Boxcar Library after delivering books to nearby mining camps. Alice secures funding from a local mine owner but meets fierce opposition from Julia Walker, the town's social matron, who argues that books will fill workers' heads with dangerous ideas. Julia's son Sidney Walker, a wealthy war veteran whose reckless behavior masks deep trauma from the trenches, quietly supports Alice, giving her his gambling winnings for book purchases: "Because once upon a time, I needed books, too" (122).
A third timeline introduces Colette Durand, daughter of Claude Durand, a copper miner and union organizer in Hell Raisin' Gulch who recites Shakespeare from memory. In 1917, Colette encounters Finn Benson, a charismatic organizer affiliated with the Industrial Workers of the World (IWW), a labor union nicknamed the Wobblies, during a strike in Butte following the Speculator Mine disaster. In 1921, hired men arrive at the Durand home demanding Claude hand over something he "found." Claude is shot dead on his porch, his last words a quote from
As You Like It: "I would not change it." The sheriff blames drifters, and Colette vows to find her father's killers.
After two years tracking a hired gun across Montana, Colette corners him at a boxing match in Shelby, where he reveals that Alice's father, Clark Monroe, not the Anaconda Copper Mining Company (known as "the Company"), paid for Claude's murder. This redirects Colette's quest: She applies for the boxcar librarian position to get close to Alice and use her as leverage against Clark Monroe.
Alice hires Colette, impressed by her knowledge of books. Colette challenges Alice to ride along on the inaugural journey, and Alice, pushed by both Colette and Sidney to stop letting fear define her, sneaks out to join. The Boxcar Library gains momentum after Colette orchestrates a campfire performance of
Pygmalion. Sidney arrives at a later camp searching for a war buddy who has died by suicide. On the boxcar roof, he reveals that he lost his entire platoon, attempted to take his own life, and that Alice's gift of
The Red Badge of Courage before the war saved him by showing he was not alone in his shame.
The 1924 timeline reaches its crisis. While Colette manipulated her way into the librarian role, Finn stayed in Missoula to undermine Clark Monroe's empire. On the boxcar, Colette holds Murdoch MacTavish (Mac), Alice's father's loyal right-hand man, at gunpoint and reveals her true identity. Mac admits he was present at Claude's murder but did not pull the trigger. Finn arrives and, when Colette hesitates, shoots Mac. Alice cradles Mac as he dies, hearing him say her first name for the first and last time. Alice and Sidney race to Missoula, but Clark Monroe dies of heart failure before they arrive. Alice delivers a devastating accusation to Colette: "You thought Mac deserved to pay, you thought my father deserved to pay. But it was me you made complicit in their deaths" (344).
Colette flees but learns that someone has placed a bounty on her. After years on the run, she discovers her hunter is Finn himself, a paid Company spy who infiltrated the union movement he pretended to champion. Devastated, Colette returns to Montana and asks Alice to plant a fake obituary. Alice agrees, then spends a decade in grief-stricken isolation, blaming herself for both deaths. Sidney leaves books on her porch for years, each with a marked passage, slowly drawing her back from despair.
In 1936 Missoula, Millie meets her staff, among them crime novelist Oscar Dalton and photographer Sidney Walker. She investigates the sabotage, noting Sidney suggested skipping three towns and that only his tribal interviews survived. On a road trip through northern Montana, she interviews Sofia Rossi, a war widow who pleads: "Don't make this pretty" (220). Oscar reveals he is actually Nathaniel Davey, the boy Alice once gave
Treasure Island, and claims Colette died over a decade ago. But in Condon, a town Sidney wanted to skip, a local contradicts Oscar, saying Colette died only a few years ago. Millie confronts Alice, who confesses: She and Sidney sabotaged the guide to protect Colette, who is still alive. Professor Thomas Lyon, the team's cartographer, had stumbled onto Colette's informal library near Condon; if that reached Helena, where Finn has political influence, Colette's cover would be blown. Together they realize Claude must have found evidence of Finn stealing Company funds.
Millie, Alice, and Sidney drive to Colette's cabin on Bluebird Pond, arriving as Finn confronts her inside. Colette has lured him with a letter reading "I found it" (386). Alice steps in front of Colette's gun, invoking a conversation about revenge they once shared over Shakespeare: "'The croaking raven doth bellow for revenge.' . . . Yet what did revenge do for that particular cast of characters? . . . Nothing good" (405-406). Millie realizes Claude hid evidence inside his books and locates the
As You Like It volume. She pries open the back cover, revealing documents proving Finn embezzled Company funds. Finn seizes Alice with a hidden knife, but Millie grabs a heavy copy of
The Complete Works of William Shakespeare and knocks him unconscious.
In an epilogue, the Montana guide is published, and Katherine accepts Millie's manuscript
Women of Montana, inspired by Sofia's plea for honesty, for a new FWP folklore program. Flo, Millie's secretary now married to Professor Lyon, surprises Millie with a typed copy prepared by the entire staff. Colette settles at Bluebird Pond, running an informal bookmobile; Finn is publicly disgraced and later found dead in an apparent suicide. Alice leaves Missoula with Sidney, traveling the country for years before Sidney serves as a war photographer in World War II. They return to Montana afterward. Sidney dies at an old age, and Alice follows two years later during a blizzard, three days past her ninety-third birthday, holding
Little Women with Sidney's photograph tucked inside: the image of the first time she was ever brave.