The prisoner of Shiverstone

"Eleven-year-old Helga Sharp is found unconscious in a drifting rowboat near the coast of Utley Island. Utley, as Helga finds out when she awakens in the hospital, is forbidden territory: it's a prison island to which the Mainland has exiled troublesome mad scientists for generations. The truth is, it's no accident that Helga landed here. While working on her projects in secret, Helga made radio contact with Erasmus Lope, a mad genius who everyone thought had died in a lab experiment gone spectacularly wrong. But Lope is alive, and Helga is on a mission to rescue him from the prison island"--Provided by publisher.