Long ago, a human managed to defeat the oldest, most powerful dragon of them all. This dragon was so strong that even the gods feared it, but it accepted its end all alone. Then, suddenly, the dragon woke up in a new life as a guy named Dolan, living in a faraway village. Living as a regular person now, Dolan works hard in the fields and hunts for food. Even though life in the village is simple, it's also cozy and makes him happy in ways he never felt as a dragon. But one day, while exploring a swamp, Dolan meets Celina, a creature who's part human and part snake called a lamia. She's looking for a partner but admits she's not great at getting humans to like her because she's part snake. Despite their differences, Dolan and Cerina start to become friends. However, they face lots of challenges from outside forces. Join them on a magical adventure as a once-mighty dragon begins a new life in a quiet corner of the world!

October 1941, as the second World War threatens to destroy the civilized world, an unforeseen complication suddenly occurs. An alien invasion! Despite the sudden appearance of these extraterrestrial aggressors, the Axis and Allies continue their destructive conflict. Only the Kishin Corps and their giant Geo-Armor Robots (a.k.a.: Kishin), developed from a captured alien robot soldier, stand between the Earth and total annihilation! A teenager, named Taishi, suddenly finds himself at the center of a struggle over a mysterious black attaché case entrusted to him by his father, Professor Tokamura. The case contains the controlling mechanism for one of the giant Geo-Armor Robots, and the Japanese Kanto Army, the alien invaders, and the Kishin Corps all want to recover the device! Between the spies, the armies, the aliens, and the Giant Robots, Taishi is in for an epic adventure—if he can survive it!

Set a few months after the original series, Wataru is called into action once again!