Zoids: Shirogane no Juukishin Liger Zero

The adventures of Allstar and his silver Liger Zero. During a battle, he and his rival Solid (who pilots a Super Geno Saurer, a variant with four long-range cannons) fall into an underground world. Allstar teams up with a girl he meets there, Party, to combat the unpiloted Berserk Führer that has been attacking villages, as his Liger Zero is foretold to be the underground world's savior and thus the only one that can stop it.