Parts: 2 (45-minute)
Writer: Glen McCoy
Airdates: 9 March 1985 - 16 March 1985
Production Code: 6Y
Megalomaniac of the Week: the Borad
Story: The Doctor and Peri's aimless wanderings are brought to a halt when the TARDIS is caught up in a Kontron time tunnel. Unable to escape its pull, they are dragged back to the origin of the tunnel - the planet Karfel, a place the Doctor once visited while travelling with Jo. Karfel has changed since the Doctor's last visit - it is now ruled by the tyrannical Borad, who monitors the entire citadel and banishes anyone who dares speak up against him. This is accomplished through the Timelash, the result of the Borad's research into time technology. No-one on Karfel knows where or when the Timelash sends its victims, and everyone lives in fear of being pushed over its threshold.
To the irritation of the planet's leader, Maylin Tekker, one of the amulets used to control Karfel's power system has been carried into the Timelash by Vena, a woman determined to keep the Borad from destroying her planet. When the Doctor and Peri arrive, Tekker sees his chance to recover the amulet before Karfel is destroyed by their incipient war with a neighboring planet. Peri is shepherded away to be secretly killed, while Tekker uses her as leverage to force the Doctor to recover the amulet.
The Doctor tracks down the amulet in nineteenth-century Scotland, where he also finds Vena and gains an extra passenger in the form of young and enthusiastic Herbert. When they all return to Karfel, the Doctor faces a dilemma - how can he keep the planet and its inhabitants safe while looking after Herbert, rescuing Peri, preventing a war and defeating the Borad? The Doctor suspects that the answers may come from within the Timelash itself...