Natural disasters have devastated planet Zi, killing off almost all life. A thousand years later humans have gradually re-established civilization, salvaging ancient Zoids through diving and mining efforts. In a village whose most previous item is a giant sword which they worship as a holy symbol. A teenage boy discovers an ancient Liger-type Zoid while on a deep water salvage operation. Suddenly the village is attacked by skeletal Bio-Zoids intent on stealing a powerful generator located in the village. Our teenage hero awakens the Liger and discovers that the town`s sacred sword is the Liger`s weapon, together they fight off the mysterious Bio-Zoids. At least for now...

(Source: AniDB)