Battle Unit Zeoth ESP (20520)

Battle Unit Zeoth takes place in the future where mankind is invaded by a race of alien robots known as the Grein. Forty-two years ago, the humans of Earth united to drive out the first invasion of the Green aliens in a fierce and costly war. However, as the Grein retreated, they left behind a secret underground base filled with self-replicating Grein machines. Ten years after Earth's victory, the secret Grein base opened and a new attack force decimated the city of New Age. To retaliate, Earth's military has deployed a mecha known as Battle Unit Zeoth, specializing in alien combat. It is the Zeoth's assignment to stop the attack force, go into the Grein secret base, and destroy the mechanical occupants before a new invasion force arrives.