As you would expect from Roddenberry there are many themes about the good and bad sides of human nature explored, and his optimism about the fate of the Human race shows through as it often does in Star Trek.
The plot follows a scientist who is researching suspended animation in deep underground caverns. He is supposed to be asleep for a week, but due to an Earth quake he is buried for 150 years.
When he awakes, he finds his world has been destroyed by war. PACS - a group of Unisex humans live underground, while the mutants (the only outwardly sign being 2 navels!)live outside.
Little is know about the ancient technology of the Nuclear Power plants and both sides fight to have the "man from the past" help them.
The moral dilema for out hero is which side he chooses to help.
Despite its age, this film ain't too bad. There's no flashy special effects , but an entertaining moral tale against slavery and oppressive regimes.
Look out for Gene Roddenberry's wife making an appearance (better known as Counsellor Troi's Mother in Star Trek The Next Generation).