Index sees an advertisement for the store's products on a billboard after asking Kamijou Touma what he could have bought with 3,600 yen instead of a reference book. After noticing her gaze at the billboard, Touma immediately tells her that no normal person would buy 3,600 yen worth of ice cream. This leads to an argument after Touma thought that Index wanted to eat ice cream during a hot summer day, even though she did not state that she was hot or hungry.