In 1830, fourteen year old Lisbet McTavish sets out on a perilous quest to find friends who will accept her unusual self and the silver mustang she has ridden so many times in her medicine dreams. Her hidden heritage links her to the spirit world of our Native Americans. She leaves Virginia and travels by keelboat from Pittsburgh, Pennsylvania to Fort Gibson, Oklahoma. On her long journey, she has to deal with thieves, river pirates, men who abuse horses, slave catchers, gamblers, and an epidemic. She becomes friends with an escaped slave, the son of an army officer, and an Osage hunter. Will she survive and find her silver mustang?