When Works Progress Administration editor Millie Lang finds herself on the wrong end of a potential political scandal, she’s shipped off to Montana to work on the state’s American Guide Series --- travel books intended to put the nation’s destitute writers to work. Millie arrives to an eclectic staff claiming their missed deadlines are due to sabotage, possibly from the state’s powerful Copper Kings, who don’t want their long and bloody history with union organizers aired for the rest of the country to read. More than a decade earlier, Alice Monroe created the Boxcar Library in order to deliver books to isolated mining towns. She thought she found the perfect librarian to staff the train car in Colette Durand. Now, no one in Missoula will tell Millie why both Alice and Colette went out on the inaugural journey of the Boxcar Library, but only Alice returned.