Peri first appeared in the Fifth Doctor serial "Planet of Fire", in which she encountered the Doctor and Turlough on the island of Lanzarote. After an encounter with the Master and the shape-changing android Kamelion (who disguises himself as her stepfather, Professor Howard Foster), Peri asked to join the Fifth Doctor on his travels, while Turlough departed to return to his home planet of Trion. (The identity of Peri's mother was not revealed in the televised series - but see below.)