'Secret Weapon' Story Code '9605' by Theodore Apstein

16th June 1956: As Doug and Tony arrive in Russia, a probe appears out of the Time Tunnel and explodes. In the present, a scientist named Doctor Biraki has met with U.S. General Parker, offering his services as a time travel expert, supposedly after realising he has been serving the wrong political cause; however, the General is suspicious of the scientist’s motives, and decides to ask the Tic-Toc personnel to check out his background. Uninjured by the exploding device, Doug and Tony receive instructions in a second F-5 probe sent by the Time Tunnel team, telling them to pose as defecting scientists, contact "Alexis", and find out about something called “Project A-13”. Mistaken for two spies named Smith and Williams, the two time-travellers are taken to Project A-13, where they find a primitive version of the Tic-Toc time tunnel project, presided over by a younger Doctor Biraki. Encouraged to examine the equipment, Doug and Tony notice that it lacks a radiation bath, meaning that whoever is sent through the Russian time tunnel will die. Their problems escalate when Biraki informs them that they have both been chosen to make the test run of the tunnel; Dog and Tony attempt to escape, but are recaptured and forced to work on improving the time tunnel. Learning that Alexis is a double-agent, Doug and Tony set about sabotaging Project A-13 – but their actions will have serious ramifications for the future of Tic-Toc…

This episode does not have a cliff-hanger.

James Darren (Tony Newman), Robert Colbert (Doug Phillips), Whit Bissell (Lieutenant General Heywood Kirk), John Zaremba (Doctor Raymond Swain), Lee Meriwether (Doctor Ann MacGregor), Nehemiah Persoff (Biraki), Michael Ansara (Hruda), Sam Groom (Jerry), Russell Conway (General Parker), Gregory Gay (Alexis), Kevin Hagen (McDonnell)

Directed by Sobey Martin
Produced and created by Irwin Allen
An Irwin Allen Production in Association with Kent Productions, Inc. and Twentieth Century-Fox Television, Inc.

TX:
US TX - 25th November 1966

Notes:
*Featuring Doctor Tony Newman, Doctor Doug Phillips, Lieutenant General Heywood Kirk, Doctor Raymond Swain and Doctor Ann MacGregor