When Mr. Hardy disappears while investigating a mystery surrounding a vacant house rumored to be either haunted or an abode for criminals, Joe and Frank search for the truth.

When the Hardy Boys set out to solve the mystery of their missing chums, they discover a gang hide-out in a cave on an island along the way.

Suspecting that their friend has been swindled, the Hardy brothers investigate and find themselves on the trail of a much larger criminal operation.

The Hardy brothers interrupt their investigations of jewelry-store holdups to answer a plea from their cousin on a New Mexico cattle ranch.

Their SOS ignored in a storm, the Hardy boys find a wallet containing two thousand dollars alongside their boat and are launched into a mystery involving diverse clues.

When their peregrine falcon brings down a homing pigeon carrying rubies, the Hardy brothers find themselves involved with kidnappers.

Teenage detectives Frank and Joe Hardy investigate a supposedly haunted house reported to be the hangout of criminals.