When Penelope and Mommy and Daddy go for a trip to the shore, Penelope decides she wants a bring a pet fish back home with her, only Mom and Dad doesn't think she's ready for a pet just yet. They stress that taking care of a pet requires patience and kindness. Worse, her two best friends now have pets of their own and aren't exactly following the rules. Will Penelope and her friends learn the value of taking care of a pet and treating animals with love and kindness?