Set in Tokyo's Shinjuku ward, the "casually science-fiction journey" unfolds in the summertime of the 21st century. The once-thriving neighbourhood is now a barren wasteland, bereft of any living beings, due to an unexplainable disaster. Among the few remnants are bizarre creatures like the "Donyatsu," a hybrid of a cat and a doughnut, and the "Begaru," a fusion of a cat and a bagel.