The hero and heroine attend the same high school, with the heroine one grade below him. They fall in love when he is a sophomore, but a month later she suddenly breaks up with him. Unable to accept it, he goes to the rooftop for some air and unexpectedly awakens the strongest System across all realms. He wants revenge on the heroine, but doesn't know she broke up with him because she was suffering from severe depression. Although he says he wants revenge, whenever he gets the chance, he keeps helping her instead. But his longing for her grows so intense that he eventually develops smiling depression. By chance, the heroine discovers his illness, and he finally learns why she broke up with him back then. At one point, he is stabbed while shielding her and ends up in the hospital. For a long time, he remains unconscious, but thanks to the heroine's steadfast companionship, he miraculously wakes up. In the end, with the System's help, the hero becomes the world's richest man and the last cultivator alive. He helps the heroine cultivate too, gives her a wedding of the century, and they live happily together.
