Nick and Bethany, immortal humans, are unicorn riders. Along with other legion members, they and their unicorns, Lazari and Shema, rescue and protect animals on earth.
After many successful trips to earth, Nick and Bethany must face a crisis closer to home. The evil unicorn, Hasbadana, has captured Nick's sisters.
When Urijah, the lord of Celestia, trades himself for the safety of the humans, Nick is determined to find a way to free Urijah from his imprisonment in the Dark Kingdom.