Rent Doctor Who: Planet of Fire (1984)

A strange signal from Earth draws the 'Tardis' to the island of Lanzarote, where Turlough (Mark Strickson) rescues a young American girl, Peri (Nicola Bryant), from drowning. Among her possessions is an artefact bearing an alien symbol - the same triangular mark that Turlough has branded into his arm. The mystery deepens when Kamelion (voice of Gerald Flood) falls under the control of a powerful mind, and the Tardis travels to the volcanic world of Sarn. As Turlough is forced to face his past, the Doctor (Peter Davison) must stop his oldest enemy from harnessing the revitalising powers of Numismaton gas...