The Drifting Classroom, Volume 7 — Kazuo Umezu

A flash flood turns the desert into a drowned world, and the students struggle to protect the school--and their precious vegetable garden--from the deluge. But just as the first vegetables are ready to harvest, the crop is infested with a strange fungus. Was all their work for nothing? Lonely for home and their parents, the students make a surrogate mother out of a statue...only to find it replaced one day by a new, terrifying idol...