Who Let the Frogs Out? is an entry in the Hardy Boys Clue Book series, aimed at younger readers. Frank and Joe Hardy are investigating a mystery at a local science fair, school, or perhaps a pet store, when a number of frogs are mysteriously released from their enclosure, causing chaos. The boys must figure out who is responsible for the mischievous act, which could range from a simple prank to a deliberate act of sabotage aimed at disrupting an important event or study. The investigation requires the boys to track the hopping suspects, question witnesses, and uncover the motive behind the amphibian escape.
