When the class pet bites the finger of Penelope, a Tyrannosaurus rex, she finally understands why she shouldn't eat her classmates--no matter how tasty they are.
As the only T. rex in her school, Penelope is often overlooked but when she loses her confidence after signing up for the school talent show, her father and some friends help her find her courage.
When Penelope Rex brings home Walter, the class goldfish, for the weekend, she is not sure how to feel, but when Walter goes missing, Penelope searches high and low for her fishy classmate.