It's midday. Metro City has fallen to the ground, President Stone has been defeated, and Astro Boy and his freinds rejoice. Just as they begin celebrating, however, a large cycloptic alien creature appears in the city and Astro Boy heads out to engage it. Before he can land a blow, however, something grabs the creature from behind and pulls it away. When Astro Boy looks n, he spots a large dinosaur-like creature with a row of maple leaf-shaped dorsal spines on it's back, which mutilates the creature, stares into it's single eye, and emits a blue beam of light from it's mouth, incinerating it's eye, then the creature drops the other's lifeless husk before turning around and spotting Astro Boy.
Astro Boy attacks the creature, to no avail, then he retreats into the city, with the creature wreaking havoc through it looking for him. The members of the Robot Revolutionary Front come out, and Sparx calls out to the creature to halt it's pursuit of Astro Boy, but Robotsky and Mike run away, and Sparx oils himself as the creature fires it's blue beam at him, incinerating him. Just then Astro Boy comes out with a steel girder, with which he whacks the creature, to no effect. Right about then, the Metro City Defense Team engages the creature, but is easily decimated in the battle.
With no other options, Astro Boy sets off a self-destruct sequence built into his hard drive, and the explosion engulfs the creature. When the dust clears, Astro Boy is gone, but the creature is still standing there, as if nothing happened. The creature then turns back the way it can and leaves, with the city in ruins, an Astro Boy's friends and family grieving.