Synopsis: Falling into the depths of depravity. ~A mating contract with a god~

During her summer vacation from university, the protagonist, Chiho, returns to her small hometown for the first time in a long time. There, Chiho and her friends decide to go on a test of courage in the forest behind the shrine. As the group ventures into the forbidden forest, they come across a place surrounded by countless paper streamers and sacred ropes. Feeling uneasy about the mysterious sound of bells and the gazes they feel, they proceed further in, when her friend Kazuya starts acting strangely...? Just as she reaches out to run to her friends, Chiho's body is seized by a mysterious arm... " I'm glad you kept your promise" "The fact that you came here means you'll become mine, right?" In her hazy state of consciousness, the mysterious man caresses Chiho's lips and body. He prepares her with cunnilingus, and finally, he thrusts deep inside her. Trying to escape the intense pleasure, she is caught by six arms, confused by the fear of something inhuman and the irresistible pleasure... "Help me, big brother..." As her consciousness falls, memories of the past resurface. "Don't break your promise, okay?"