Penguin Science Fiction: The Ark Sakura

In anticipation of a coming nuclear apocalypse, Mole has converted a huge underground quarry into an 'ark'. While searching for his crew, he falls for the tricks of a wily insect dealer and his friends. In the surreal drama that ensues, the ark is invaded by first a gang of youths and then a sinister group of elderly people, before Mole himself becomes trapped in the ark's central piece of equipment - a giant toilet powerful enough to flush almost anything out to sea.