The Master, in the guise of Professor Thascalos, has constructed at the Newton Institute in Wootton a device known as TOMTIT - Transmission Of Matter Through Interstitial Time - to gain control over Kronos, a creature from outside time. The creature is summoned but proves to be uncontrollable.
Producer: Barry Letts
Director: Paul Bernard
Writer: Robert Sloman, Barry Letts
The Doctor
Jo Grant
The Master
Brigadier Lethbridge-Stewart
Captain Mike Yates
Sergeant Benton
Galleia
Dr. Ruth Ingram