To escape her strait-laced overbearing sister, Birdie Stauffer auditions for the all-female Versatile Quintet, Chautauqua circuit's opening act. Through this train-traveling roadshow she experiences the tumultuous 1920s, a modern era of shocking flappers and smuggled whiskey, with the camaraderie of newfound friends. Her exceptional gift of concert whistling entertains more than songbirds as she gains national notoriety and she's soon entangled in two romantic relationships—one with a dapper circuit manager, the other her fellow pianist. Accompanied by four other musicians—a slang slinging flapper, a confident girl-next-door, a tight-lipped loner, and a virtuoso sapphic—and following a series of traumatic events, Birdie discovers even the best relationships can be filled with misunderstandings. As she learns to trust her intuition, she finds it may cost her love interests, her sister, and maybe even herself.