Piro's sketchbook contains a collection of his drawings, mainly of sad or troubled looking girls. He loses it together with his bag while knocking down a display in a manga-shop. It is picked up by Yuki who, impressed with the quality, declines to involve her dad in returning it. She then starts to annotate these drawings.
Yuki was inspired by the sketchbook to ask Piro for drawing lessons. Yuki is shown with her own sketchbook and pencils when she shows up for her first lesson, which Piro misses. She brings it again and shows it to Piro when the lesson finally occurs.