Nanami brings a kotatsu over to the house before leaving for work. Mitsuki then sees it and uses it while studying math but falls asleep followed by Hiyori. When Yüya sees Hiyori sleeping with Mitsuki he assumes she is a friend. After noticing her math book he sees that she has the wrong answers, and corrects them for her under the kotatsu before falling asleep as well. Mitsuki awakens to find Yüya holding her while sleeping causing her to unsuccessfully try to awaken him with a slap. She dismisses it as him being an airhead, but is touched when she finds the corrected math work he did...