Kusuo Saiki, who wants nothing more than to be left alone, is talked into a spring-break trip to the town of Oshimai with Nendou, Kaidou, Teruhashi and the rest of the class. While the group enjoys the getaway, a volcanic eruption big enough to bury Japan in lava and ash is building, and Kusuo has to head it off without anyone seeing him do it. This special adapts the manga's concluding chapters and closes out the TV series.