Max, a friendly mouse leaves the safety of Mouse Town to go in search of adventure, and instead meets humans, Sara and Lea, and develops a meaningful bond with them that lasts a lifetime. At first, Max is scared of them, but he soon learns that Sara and Lea are different than other humans, and they all become the best of friends. The girls ask Max to be their pet mouse and he agrees, however, their friendship is thwarted by interspecism (belief in the superiority of a particular species or the separateness of a species as a whole) and their happiness is short lived. This story is all heart as the girls mother finds out about their unique friendship with Max and tells the girls they can't keep him as a pet. Sadly, Max and the girls are separated. Max finds his way back to his mouse family and while he's happy to be home, he misses Sara and Lea very much. Max knows, no matter what, he will always be their friend. There is a back-drop of tolerance as Max's father comes to recognize that his faltered attitude toward humans are because of his own misunderstandings about humans, and the girl's mother comes to a similar conclusion, believing that anyone who loves her children that much can't be all that bad. In this friendship, there are many obstacles that the girls and Max must face, and as time goes by, a lesson in loyalty, and acceptance is learned by all involved.