The Power Dragon came to Earth from a distant planet, following an alien civilization that came and hid their city by disguising it as a thunderstorm. After the Power Dragon attacked some ships at sea, the Calico was sucked by the storm into the city, and the Power Dragon attacked. The aliens freed Godzilla from the storm's eye and Godzilla came and drove off the Power Dragon.
After realizing Godzilla's power, Ze-us, an alien, teleported Godzilla to their planet. When the Calico crew started fighting the aliens, the Power Dragon came back and destroyed the teleporter with a lighting bolt. The Power Dragon went after the Calico crew, who had Ze-us' mental amplifier, but Dr. Darien used it to bring Godzilla back. Godzilla and the Power Dragon fell down the storm's eye into the ocean, where the Power Dragon shorted out the generators that kept the storm in form, and it and the aliens disappeared.