rina, a caregiver, lives with her fiancé kenji and his grandfather shūzō. wanting to support kenji, who works while caring for his grandfather, rina offers to take care of shūzō. however, shūzō subjects rina to merciless sexual harassment, driven by his desires. rina initially resists but gradually accepts him, seeing her late grandfather in shūzō. their twisted sexual relationship begins. #banchō p