The Giants have invented a chemical that forces those exposed to it to tell the truth, and plan to test it on the Earthlings.

The Earthlings come to the aid of a giant deaf boy and his poverty-stricken family.

Inspector Kobick of the SID involves the Earthlings in a plan to track down counterfeiters.

Two time travellers from 5477 come to the Land of the Giants to conquer Earth.

Barry and Valerie are carried off in a balloon to a distant land ruled by a malevolent dictator.

Fitzhugh and Steve accidentally return to Earth in a space-time pod but end up in 1900 and must deal with hostile villagers.

While working with a helpful Giant scientist, the Earthlings are subjected to radiation which causes strange hallucinations.

The Earthlings aid an injured puppeteer by pretending to be his dancing puppets, but the owner soon suspects they are involved and prepares to capture them for the reward.

Using a device stolen from time-travelling researchers, Steve and Dan return to the day of the Spindrift's launch and try to alter history and stop the ill-fated flight.