The story is a fantasy; but the core interest of the book is the normal family life of an eight year old girl, Non-chan (short for Nobuko), her mother, father and older brother. One day Non-chan wakes up to find that her mother has gone with Non-chan's brother to visit relatives in Tokyo. The family had moved to the countryside after Non-chan as a small child became desperately sick with dysentery. Her mother had once promised Non-chan that she could come with her to Tokyo when she was older and stronger. Now she has gone off, keeping the trip secret. Non-chan, feeling betrayed and deceived, cries with unusual persistence.
'Well that's because everybody is worried about you.'
'That's a lie! Brother's never worried about me or anything.'
Father gave up and turned away. 'What a child for not seeing things! Go on and cry!'
'I am crying. Waaaah.'
And Non-chan cried.
Aunt had been tidying up the breakfast plates in the kitchen. When she came out a little later, father's silence and Non-chan's crying was still continuing. Aunt crouched down next to Non-chan and helped her blow her nose again and wiped her eyes.
'Come on, Non-chan,' she said, 'Please stop crying like that! Mother's already got to Yotsuya by now. Crying won't change anything, you know. Instead of that, let's you and me go out somewhere.'
'Now there's a good idea,' father agreed.
But Non-chan kept on crying.
What good was all that? Father and aunt didn't understand. She was crying, because she couldn't change anything.
Non-chan goes out to a nearby pond and climbs the tree there, gradually calming down. Suddenly she finds herself floating in the air, able to move each way, so that it becomes hard to tell 'up' from 'down'. She hears a voice calling her from a cloud overhead and dives upwards to reach it. The cloud is being steered by a strange kindly old man, who reminds Non-chan of her grandfather and also of a figure in her ohinasama dolls set. He is ferrying several people across the sky, but somehow the only one Non-chan can see clearly is a boy from her class.
The old man asks her about her life; and most of the book then becomes Non-chan's account, rephrased by the narrator, of herself and of her father, mother and brother. After each story, the old man questions her and makes suggestions, which put a new light on the story and its characters. Although Non-chan claims that their family is a happy one, it gradually emerges that she and her brother do not get on perfectly. Complaints about her brother creep into her stories of her mother and father, so that when we get to the chapters devoted to the brother we expect more of the same. In fact, Non-chan recognises good things in her brother too, and the relationship does not sound especially bad. He is a wild and thoughtless child, while she is a proper and disciplined one. Under the old man's prompting she comes to see his point of view.
This probably sounds like the book is describing a counselling session, "Non-chan's Supernatural Therapist". Probably part of its appeal is the idea of having someone interested to hear all about a child's life (a fairly rare experience for most children). As far as the fantastic element is concerned, a magical figure has more authority in its suggestions and judgements; but the book lives by its depiction of a family.
There is no English translation, but there is a German one, by Aenne Sano-Gerber, Nobbi, Erlebnisse einer kleinen Japanerin (1956), which in turn was translated into Danish as Nobbi, en lille japanesk piges oplevelser (1958). Both are out of print, but there are second hand copies. If you're looking, you may want to search for Momoko Ischii, which seems to be how the name is transliterated in the books.