Although there is no blood relationship, the brother-in-law always cherished his kind younger sister Yui. One day, their father went on a business trip. As soon as they saw him off and were alone, the brother-in-law changed drastically. His twisted affection was directed towards Yui. Yui was confined in a room and toyed with. Initially, Yui resisted, but she was violated and brainwashed by her monstrous brother, and then fell into a distorted love...
