Five contemporary black women friends from Kansas City, Missouri take a weekend train trip as part of their book/wine club. Marie, a librarian, in addition to arranging the trip, is also doing research for her grandmother’s 80th birthday which involves looking through “The Negro Motorist Green Book,” the guidebook used by African-Americans in pre-integration America to know the safe places to stay and patronize while traveling. Marie accidentally time travels to the 1940s, where she stays in a boarding house mentioned in the Green Book. But not only has she traveled to Jim Crow Missouri, she finds herself staying in a boarding house that is actually a bordello, and where one of the “working girls” may be her great-grandmother. (The four women in the past that Marie meets are double cast with her friends on the train trip.)