Episode Three
Series Episode Number: 320World Premiere: Sat 22 Apr 1972 - 5:50pm BST [BBC One] (United Kingdom)
First Broadcast: Wed 1 Oct 1975 - 6:30pm CDT [WTTW 11 Chicago]
Running Time: 24 minutes 32 seconds
7.90 Million (UK)
Chart Position: 36 () (UK)
Recorded on Mon 13 Mar 1972 in TC8
Archive State: PAL 2 VT
Ky opens the message box but cannot understand the ancient carved tablets inside. The Marshal seals the Doctor and his friends in the caves and prepares to gas them to death.