This four-part "Doctor Who" serial finds the Doctor (Peter Davison), his companion Turlough (Mark Strickson) and the android Kamelion (Gerald Flood) touching down on the island of Lanzarote, where they arrive just in time for Turlough to save an American girl (Nicola Bryant) from drowning. But their chance meeting seems more than coincidence when she produces an object that bears the same symbol that's branded on Turlough's arm.