As an extremely rare monster, dream monsters like to devour other people's dreams. In the dream, they possess the protagonist's body and experience various encounters in the dream with him.
As a little dream monster, Yotsuba, like her mother, has had the habit of writing a diary as long as she can remember.
And her diary recorded every dream she experienced.
Please don't open the dream monster's book easily, because you don't know when you will fall into the dream in the book.
Concept: A simple collection of small articles