United States Senator Leroy Clark arrives from Washington, DC, to investigate the progress of Project Tic-Toc in Arizona. He is met outside the subterranean complex by Dr. Doug Phillips, who ushers him in. They are met by Lt. General Heywood Kirk, known to Clark as his former commanding officer when he was a paratrooper in the army. As chairman of the Senate committee overseeing the Time Tunnel, Clark lets it be known that he can either authorize the continued funding of the project or cut...

Tony and Doug arrive on the island of Krakatoa the day of its eruption in August 1883 just in time to stop the sacrifice of a young Indonesian by his companions, who are there to serve as guides to Dr. Holland and his daughter. Dr. Holland is conducting a scientific investigation of the island following the loud volcanic explosion a few months before. Karnutu, the chief guide, believes Doug and Tony are devils, who are causing the eruption, and he tries to sacrifice them to the fires to st...

Tony and Doug arrive on the French penal colony of Devil s Island just as new prisoners arrive. They are mistaken for two of the prisoners who have escaped and are imprisoned in their stead. The other prisoners are not interested in escape until Captain Alfred Dreyfus arrives on the island, but this is part of a scheme of the French government to eliminate Dreyfus by killing him if he tries to escape.

Tony and Doug arrive on the island of Krakatoa the day of its eruption in August 1883 just in time to stop the sacrifice of a young Indonesian by his companions, who are there to serve as guides to Dr. Holland and his daughter. Dr. Holland is conducting a scientific investigation of the island following the loud volcanic explosion a few months before. Karnutu, the chief guide, believes Doug and Tony are devils, who are causing the eruption, and he tries to sacrifice them to the fires to st...

Tony and Doug land in 1876 Montana the day before the Battle of the Little Bighorn. They are captured by Chief Crazy Horse and his companions, and Doug manages to escape with the help of the survivor of a troop of soldiers, Trumpeter Tim McKinnis. Tony does not escape and is taken to the Sioux encampment. There, he demonstrates his honesty and bravery to Chief Sitting Bull, moving him to adopt him. Doug and Tim make their way to the 7th Cavalry for help.

In 1815, during the conflict between the Americans and English during the Napoleonic Wars, scientists become prisoners and sentenced to death, but receive help from the Time Tunnel that sends to them another traveler of the future, a British military of 1968.

Tony and Doug are transported through the Time Tunnel into the service module of a spaceship just before liftoff. The spacecraft, part of the M.E.M. (Mars Excursion Module) ten years into Tony and Doug s future, it will be the first manned US spaceflight to Mars. Tony and Doug s added weight (335 pounds) makes it impossible for the spacecraft to reach escape velocity to escape Earth s gravitational pull. Unbeknownst to the stowaways, the astronauts on board decide to eject the service modu...

United States Senator Leroy Clark arrives from Washington, DC, to investigate the progress of Project Tic-Toc in Arizona. He is met outside the subterranean complex by Dr. Doug Phillips, who ushers him in. They are met by Lt. General Heywood Kirk, known to Clark as his former commanding officer when he was a paratrooper in the army. As chairman of the Senate committee overseeing the Time Tunnel, Clark lets it be known that he can either authorize the continued funding of the project or cut...

Tony and Doug are transported through the Time Tunnel into the service module of a spaceship just before liftoff. The spacecraft, part of the M.E.M. (Mars Excursion Module) ten years into Tony and Doug s future, it will be the first manned US spaceflight to Mars. Tony and Doug s added weight (335 pounds) makes it impossible for the spacecraft to reach escape velocity to escape Earth s gravitational pull. Unbeknownst to the stowaways, the astronauts on board decide to eject the service modu...