Student and teacher, nephew and aunt Kyuuichi and Saeko are in a forbidden lover relationship that cannot marry. This relationship was a secret to everyone around them, including Shihou, who is Saeko's daughter and Kyuuichi's cousin. One day after school, Shihou is called by Terushima, rumored to be a perverted teacher. There, she suddenly sees photos of Saeko in compromising positions. According to Terushima, the photos were sent to the school along with a blackmail letter. Demanding money or replacement photos, Shihou, thinking of her mother, agrees to have her photo taken on the condition that her face would not be shown. However, this was a vile trap set by Terushima！！
