A twelve-year-old boy named Sato Yuu is subjected to daily abuse by his stepfather, who harbors a massive debt and takes out his frustrations on the boy. His mother cowers in fear and does nothing to protect him. One day, his stepfather kills him for the insurance money. As he dies, Yuu thinks about how he has always been the one deprived and stolen from, and vows that if he is reborn, he will become the one who takes instead.

He awakens in an unfamiliar house in a fantasy world that operates like a video game, complete with visible status screens and skills. A kind old woman named Stella Ford takes him in and teaches him to read and write. Yuu's black hair and eyes mark him as an outsider, and the villagers despise him. He trains to become strong enough to protect Stella. When the villagers threaten to harm her, Yuu's intense desire to stop being robbed awakens a unique skill called Depriver, which allows him to steal skills from others. The skill has conditions: he must maintain eye contact with the target, be within about one meter of range, and has a success rate that is not guaranteed. Using it also causes headaches. He also possesses a second innate skill called Strange Eye, which lets him see the skills of others and works perfectly in tandem with Depriver.

After stealing skills from village bullies and local creatures, Yuu begins to grow stronger. A red-haired female adventurer named Nina becomes fixated on him and follows him around, insisting on being his friend despite his distrust. Later, a mage named Lena Forma, who calls herself a genius but has poor stamina, joins their group. Together, they head toward the city of Kamaa to register as official adventurers at the guild. There, Yuu attracts the attention of a legendary adventurer nicknamed Strong Arm Josef, who challenges him to a one-on-one duel. The trio then faces their first dungeon, and the successive trials begin to forge them into a proper party.

The story traces Yuu's journey from a revenge-driven boy who wants to take everything from those who wronged him to someone who uses his power to protect the people who have accepted him. He learns to trust others, and the focus shifts from retribution to safeguarding his new companions. The narrative follows his growth as he steals increasingly powerful abilities, confronts discrimination and oppression in the new world, and gradually builds a place where he belongs.