Doug and Tony are transported to the Grand Canyon, Arizona, in 1547. Meanwhile, the saboteur Raul Nimon kills Dr. Alfred Stiles and plants a nuclear bomb with a timing device in the phase synchronizer console; however, the security seals all the exit and Nimon escapes through the time tunnel that is fixed in Doug and Tony.

Cast: James Darren, Robert Colbert, Robert Duvall, Vitina Marcus, Lew Gallo, Whit Bissell, John Zaremba, Lee Meriwether, Wesley Lau, Joe Ryan