After being excommunicated and thrown out of his home by his only living relative, his brother, following the death of their parents, a recluse neet Keiji is recommended for a live-in janitorial job by his brother, Shougo. However, he's forced to use a false name to hide their blood ties and faces constant belittlement in his new position. Despite daily struggles, Keiji finds comfort in his interactions with a pure-hearted female student called Kasumi, but harsh reality pushes him deeper into despair. Kasumi has a mild crush on Keiji's brother, who is secretly involved in a physical relationship with her older sister Yuuka. However, Shougo reveals his vile nature and begins lusting after Kasumi as well. Keiji, feeling sorry for Kasumi, tries to keep her safe from his brother's advances but fails spectacularly, causing even Kasumi to despise him. Driven to his limit, Keiji decides to seek revenge on his brother and those close to him. The revenge story of a recluse neet man has just begun.