A surviving fragment of Sosai X mutates into Sosai Z and recruits megalomaniac Count Egobossler to create an army to conquer the world. To combat this new threat, the Science Ninja Team Gatchaman once again return with newer weapons and a new ship - the Gatchaspartan. But with the new weapons comes a heavy price: the more Ken the Eagle uses his weapon Gatchafencer as part of the Gatchaspartan's ultimate weapon, the weaker he gets as the weapon mysteriously and slowly drains his life force.