In the near future, the world's earth resources will be exhausted, and the vast ocean will become a new target for development. One day, a young boy with a sense of justice, Lei Minghai, was driving a "heavy armored machine soldier" robot to collect mineral samples on the seabed. Suddenly, countless satellite laser beams fell from the sky, which surprised the idol singer Tianyin who was holding a concert tour. He was attacked and fell into the sea, but fortunately he was rescued by Lei Minghai who was passing by.

The sudden attack wiped out all the armed advanced countries in the world, and the world fell into a state of collapse. However, the underwater city "Nautilus City" [Note 1] located in the depths of the Northeast Sea of ​​Taiwan , although it escaped the attack of laser beams, it is believed that the underwater city that cannot be attacked by lasers is safe and sound, so the remaining forces in the world Assemble to Taiwan and use the deep sea as a base to launch a Jedi counterattack, but find that there are more dangerous "undersea monsters" in the deep sea that are quietly attacking the seabed city. Lei Minghai will lead the heavy armored mecha team to save the world.