I'm engaged to a liar, but the teacher does his best to protect me. His skills are top-notch! Nobuko pretends to be engaged to a handsome doctor, Dr. Hitoshi Akao, aka "Red Oni", who is too much of a devil for his job. She is nervous about the strict doctor, but she can't stop pounding her heart as she learns about his sweet tooth, shyness, and other aspects of him that she didn't know existed! She also persuades her overprotective older sister, who stubbornly refuses to approve of her marriage, to "leave her to me".... But he never expected that they would end up living together.... What will happen to this fake engagement?