Kai, a young man who entered the institute at a young age and became the chief spacecraft researcher (tool), became a fleet commander for the first time at the same time that a rebellion broke out in his country. However, he and his childhood sweetheart Ti were unfortunately defeated during the battle with the rebels and fled on their own. Ti also did not know whether he was alive or dead in order to protect him. Under the guidance of the deputy captain, the grief-stricken Kai experienced the ups and downs of life, slowly grew up, matured mentally, and finally conquered the empire that was captured by the rebels.