Part A: The winter is almost over. The gang divide themselves into two teams and play snowball but Mayoi and Sakaki have some tricks up their sleeves.

Part B: Cooking class. In a different team than Io, Tsumiki takes the opportunity to show him her culinary skills.

The time comes for the school festival and the five decide to mount a crêpe stand (named "Tsutsumin!" meaning something like "I wrapped") together, which turns out to be a great success. Io serves as the cook but also sews Tsumiki's mascot uniform by hand, and promises the first crêpe to her. Mayoi wears no lab coat over her waitress uniform.