Five teenagers become the last line of defense for the galaxy in an intergalactic battle against the evil alien force led by King Zarkon.

After Keith, Lance, Pidge, Hunk, and Shiro are sent into space in a blue lion, they find two "Alteans", Allura and Coran who have been frozen in cryopods for ten thousand years. They then discover they must each pilot the robotic lions of Voltron, and defend the universe from the "Galra", and their evil emperor Zarkon.