It's just another day in modern Tokyo. A cute schoolgirl (or schoolboy, if you're so inclined to choose) is walking down a metallic pathway, when suddenly, robotic ape/lizard hybrids leap from nowhere, only to be slashed in twain with your sword that leaves a shower of sparkles in its wake. Reinforcements come in from all sides as you continue to press your way to the right. A large humanoid robot attacks, its lanky limbs forcing you to keep your distance. You hold your attack button, and after a moment you unleash your full power.
A ball of energy rockets forth, defeating the robot and immobilizing it, but not destroying it. You climb into it, and take the controls. Bounding forward, the enemies that once caused a little trouble are completely decimated by your robot's newfound ability to blast the foes with tongues of lightning.