Oinarisama. Eating Oneself to Ruin

On the way home from school, Noboru and Sakura stop by a bookstore where they meet up with Kou and Kuugen. On discovering that Kou came there to get a book by which she could teach herself to cook, Sakura invites herself over to Noboru's place by offering to teach her. Kuugen is bribed by the offer of a homemade chocolate cake. Later when Sakura drops by, Kuugen manages to disrupt the entire cooking process by coating the entire kitchen with cocoa as a part of her research into the chocolate cake's ingredients. To placate the tantrum throwing Kuugen, who still wants to eat cake, Sakura offers to take to the girls to an all-you-can-eat cake buffet. At the buffet, while Kuugen eats herself to distraction, Sakura and Kou get to know each other better. On the way home, they meet the Takagami brothers who have managed to attract the attention of a few low level Book-dwelling Spirits. Kuugen promptly vanquishes them and once again seals Sakura's memory, but someone else has been watching Kuugen's display of power from the sidelines.