Fenton Hardy, the famous private detective and father of the Hardy Boys, asks his sons to help him with his latest case involving the illegal drug trade. Hardy sends Frank and Joe to a house on the cliff, whose location offers an excellent vantage point to watch for smugglers. The Hardy Boys are tricked into going inside the house by cries for help and find themselves trapped for a short time in the attic, meanwhile, their telescope and motorcycles...

On an ice-bound, snow-covered island, Frank and Joe attempt to solve the mystery of a boy's disappearance and the theft of a priceless collection of antique medals.

Frank and Joe solve a mystery involving the disappearance of a professor, a hot-tempered hermit, sabotage at the new Bayport Coastal Radar Station, and the Honeycomb Caves.

Frank and Joe, the Hardy boys, solve a mystery involving a magician, American secret agents, an international spy ring, and a Scottish castle.

Helping in a case their father is working on, the Hardy brothers try to find an informer who has telephoned from a booth in their home town, and are hired by a carnival owner to spot pickpockets.