Dink, Josh, and Ruth Rose get an urgent call from Mrs. Davis. Her canary is gone! And that's not all. Three other pets have mysteriously disappeared--including Ruth's cat, Tiger! The kids are sure a pet-napper is to blame. They won't stop until they've tracked down the theif and returned the stolen pets to their rightful owners!.
While picnicking on Squaw Island, Dink, Josh, and Ruth Rose find a hundred dollar bill, and when they return to explore further they find an entire cave full of money.
Dink, Josh, and Ruth Rose investigate the theft of a great deal of money from the belly of a nearly life-size Tyrannosaurus Rex model that their friend, Jud Wheat, is using to raise money for a dinosaur museum.
Dink and his friends meet an exchange student, Sammi, who is actually the prince of an island country, hiding from those enemies who have kidnapped his parents and who may be after him as well.