The future in parallel time and space is a world with mechanical life. Here, humans and robots cannot be distinguished by appearance alone, because the robots here can also grow and develop, even have body temperature and blood, and rely on a human brain-like thinking structure to think independently, almost like humans. The only difference is that when they reach adulthood, their appearance will never age until the mechanical organs in their bodies can no longer be replaced.
But having such technology comes at a cost. This world is constantly at war, and humans and robots have never achieved true peace. At this time, humans joined hands with roboticists to create new war robots, allowing them to live in battle for the rest of their lives.
Mechanical mercenary Xiu Ye is one of them. But he is considered a complete failure in the eyes of most humans and robots, simply because he has two bodies and two personalities like a patient with schizophrenia. According to his maker, Xiu Ye originally had a robot sister named Xiunas, who later died on the battlefield. Xiu Ye didn't know how to put Xiunas into his body, and from then on he and Xiunas lived together. In order to find out how Xiu Ye did it, someone deliberately hired some mechanical mercenaries who could steal secrets to find the answer. But they all returned in vain or were killed by the elite Xiu Ye. Later, Xiu Ye disappeared from the battlefield, and this issue was forgotten by everyone...
Seven years later, a male mechanical mercenary named Ling Erxiu saw the long-haired and extremely beautiful Xiunas on the battlefield with the enemy. She destroyed a group by herself, but she also ran out of energy and passed out...