A young boy, Ruuji Familon, is assisting his father in recovering a Zoid from the bottom of a lake when his village is attacked by silver-plated "Bio-Zoids". None of the villagers are able to pilot the excavated Zoid, until Ruuji accidentally falls into the cockpit and activates it. He names the Zoid "Murasame Liger", and, with it, is able to fight off the invaders.