They say whatever doesn’t kill you makes you stronger, but that’s not the case for the world’s weakest hunter Sung Jinwoo. After being brutally slaughtered by monsters in a high-ranking dungeon, Jinwoo came back with the System, a program only he could see, that’s leveling him up in every way. Now, he’s inspired to discover the secrets behind his powers and the dungeon that spawned them.

Amane lives alone in an apartment, and the most beautiful girl in school, Mahiru, lives just next door. They've almost never spoken—until the day he sees her in distress on a rainy day and lends her his umbrella. To return the favour, she offers him help around the house, and a relationship slowly begins to blossom as the distance between them closes…