Yamada and Kase-san. (4) "Isn't it like a dream that we'll be together from now on?" Yamada and Kase-san are searching for a place to share a room. What kind of place should they choose? What should they put in the room? The two are excited with fun imaginations. Meanwhile, Fukami, who shares a room with Kase-san, is shocked to learn that Kase-san is leaving the dorm and challenges her to a 100-meter race with her dormitory exit on the line. What will be the outcome of this match...? A serious competition with no holds barred, where feelings that can't be given up spark like fireworks. The sparkling youth diary of Yamada and Kase-san, the fourth installment!!