ぼくと猫と満月の夜 (Boku to neko to mangetsu no yoru, Me and the Cat and the Night of the Full Moon, 2008) is a fantasy juvenile detective story by MATSUO Yumi (松尾由美). It was first published as フリッツと満月の夜 (Fritz to mangetsu no yoru, Fritz and the Night of the Full Moon). My edition is a revision of this, which adds a short story with some of the characters of the original novel, 小早川ミツルと消しゴムの謎 (Kobayakawa mitsuru to keshigomi no nazo, "Mitsuru Kobayakawa and the Puzzle of the Erasers").
The narrator Kazuya is boy in the fifth year of primary school (which would make him about eleven). His father, a writer, brings him to the quiet seaside town where the story is set, for a few weeks in the summer holidays, while he finishes work on the book. Kazuya is an unremarkable boy. His only special ability is running. He seems intelligent, but not especially so. His narration is marked by a tendency to see the other (mostly negative) side of anything he talks about, often noted in little parentheses and afterthoughts. He soon becomes friends with the son of a nearby café owner, Mitsuru, an enthusiastic mystery reader.
Mitsuru is investigating a little local mystery on his own. Some years back a rich and eccentric woman had taken her whole fortune out of the bank. Although she had had no contact with anyone in the days between that and her (natural) death, the money had disappeared. Mitsuru has heard some clues to this fortune and wants to find it, to prevent it falling into the hands of the mayor, who thinks he has a right to it and wants to cut away the wooded hill above the town to build a golf course.
Mitsuru and Kazuya's investigation is helped and hindered by a thief with a hopeless sense of direction, the mayor's bullying grandson, and a strangely intelligent cat with a gold earring in one ear. The cat, Fritz of the original title, provides the fantasy element of the story. But fantasy does not dominate the narrative; and for the most part the setting is a more or less realistic description of a small seaside town.
The book is probably suitable for children around the age of the main characters, although my edition was not generously provided with furigana in the way that children's books generally are. There is no actual violence, although it is sometimes threatened. The first half of the book felt a little underpowered. The various mysteries were all small affairs, and I couldn't see enough of any of them to really feel involved. But towards the middle, the action and the progress of the investigation picks up.
The short story is in the tradition of "puzzles of everyday life". Mitsuru is pressured into investigating why a fellow schoolboy's older sister is secretly buying erasers. Can she be planning to rub out the sketches of her rival in art class? If not, what can she be planning?