A chilling horror tale depicting the sinister traditions rooted in a family bloodline. After being told by his parents to check on his grandmother who lives alone, a college student travels to the countryside with his older sister. Not only does their grandmother show signs of mild dementia, but she also believes in a strange entity known as “Mentori-sama.” According to the old saying, “If you do something bad,Mentori-sama will come for you.” What exactly is this eerie being called Mentor-sama?