As the Calico investigates a strange electromagnetic power source beneath the sea near the Bali Trench, an oil tanker is sunk by what appears to be a bolt of lightening that originates underwater. As Dr. Darian, Brock, and Godzooky travel underwater in the bathysphere, they are attacked by the source of the lightening bolt, the Megavolt Monster, an aquatic kaiju that resembles a giant electric eel. The monster severs the bathysphere's umbilical cord, and the craft ends up landing on an underwater desert that's protected by an air bubble. There the trio discovers an entire colony of Megavolt Monsters who acquire their electrical power by feeding off an electrolyzed outcropping of stone, which appears to be the mysterious power source that the crew first investigated. After battling the first Megavolt Monster to a standstill to save the Calico, Godzilla arrives at the underwater desert to save the bathysphere crew, and he penetrates the air bubble, causing the sea to rush in and de