A renegade human prototype Cybergirl crash-lands on Earth to explore the humanity on which she is partly modelled. She takes refuge with fourteen-year-old Jackson Campbell and his bemused father Hugh, who welcome into their family this young stranger with such astonishing powers. Desperate to experience life in the glorious metropolis of River City, Cybergirl assumes a human identity as Jackson's cousin Ashley, and so begins her exploration of the challenges and excitement of life as a teenage girl.