In Missouri, 1849, Samantha dreams of moving back to New York to be a professional musician — not an easy thing if you're a girl, and harder still if you're Chinese. But a tragic accident dashes any hopes of fulfilling her dream and, instead, leaves her fearing for her life. With the help of a runaway slave named Annamae, Samantha flees town for the unknown frontier. But life on the Oregon Trail is unsafe for two girls, so they pretend to be Sammy and Andy, two boys headed for California and the gold rush.
Sammy and Andy forge a powerful bond as they each search for a link to their past and struggle to avoid any unwanted attention. But when they cross paths with a band of cowboys, the light-hearted troupe turn out to be unexpected allies. With the law closing in on them and new setbacks coming each day, the girls quickly learn that it's difficult to hide on the open trail.