When ancient demons threaten to reclaim the city of Mariner Bay, five young heroes are recruited by the military organization known as Lightspeed to harness amazing technological powers and defend the city from destruction.

Lightspeed was situated in the Lightspeed Aquabase, which lay deep beneath the ocean off the coast of Mariner Bay. It consisted of several domes, and housed the Zords. The Aquabase was destroyed by Queen Bansheera.