Sam is a mouse who lives in a library. He loves to read all kinds of books and he learns that he also loves to make up and write his own stories, just like the books he finds in the library. He begins to leave his stories in different parts of the library: the mystery he writes he places alongside the other mysteries; the fairytale goes with similar books and so on. Humans find his stories and want to know who the writer is. So Sam, who is a bit cautious around humans, devises a plan to introduce them to the writer inside themselves.