Big charge!! Bottom of new sea stronghold Rood

Synopsis

The Mechanical Beast Rocket R2, launched from the undersea fortress Bood, has been rampaging through the city. Rocket R2 packs a serious punch — it absorbs solar energy with its helmet, converts it into a laser beam, and fires it from the buckle on its waist. Even in bad weather, it can stockpile energy by sending the helmet up above the clouds and still get off a beam. Mazinger Z aims for that helmet, but can't manage to destroy it before the Photon Power Laboratory comes under attack.