Tony and Doug become participants in past events such as the sinking of the "Titanic", the attack on Pearl Harbor, the eruption of Krakatoa, Custer's Last Stand, and the Battle of the Alamo, among others. General Kirk, Ray, and Ann in the control room are able to locate them in time and space, observe them, occasionally communicate with them through voice contact, and send help. When the series was abruptly cancelled in the summer of 1967 by ABC, they had not filmed an episode in which Tony and Doug are safely returned to the Time Tunnel complex.