Pearl and Wagner, a rabbit and a mouse who are best friends, learn about secrets during a trip to an ice cream factory and an amusement park birthday party.
April Fools' Day is not a happy one for Wagner the mouse because his best friend, Pearl the rabbit, and other children and adults at school keep tricking him.
Rhino's impetuosity and housemate Mouse's meticulousness clash in comic fashion as the friends celebrate a holiday, get Rhino out of a tight spot, and dress up as each other for a costume party.