Set fifteen years in the then-future year 1983, the series tells the tale of the crew and passengers of a sub-orbital transport ship named Spindrift. In the pilot episode, the Spindrift is en route from Los Angeles to London, on an ultra-fast sub-orbital flight. Just beyond Earth's boundary with space, the Spindrift encounters a magnetic space storm, and is dragged through a space warp to a mysterious planet where everything is twelve times larger than on Earth, whose inhabitants the Earthlings nickname "the Giants". The Spindrift crash-lands, and the damage renders it inoperable.

A teenage boy tries to train an unruly birddog.