'The Cool Caveman' by Alan Fennell

Struggling with the difficult decision on what to wear to Atlanta's fancy dress ball, Troy falls asleep. He dreams of encountering a race of underwater cavemen who have plundered the cargo of a vessel carrying radioactive material…

Don Mason (Captain Troy Tempest), Robert Easton (Lieutenant George Lee ‘Phones’ Sheridan / Agent X20), Lois Maxwell (Lieutenant Atlanta Shore), Ray Barrett (Commander Sam Shore / Lieutenant Fisher / Titan)

Directed by Alan Pattillo
Produced by Gerry Anderson

TX (UK): 31st January 1965

Notes:
*Featuring Captain Troy Tempest, Lieutenant George Lee 'Phones' Sheridan, Commander Sam Shore, Lieutenant Atlanta Shore, Lieutenant Fisher and Marina