Fenton Hardy, the famous private detective and father of the Hardy Boys, asks his sons to help him with his latest case involving a criminal named Snattman and the smuggling of stolen drugs.

Frank and Joe solve a dangerous mystery involving a payroll robbery, a mine cave-in, a piano playing ghost and bobby-trapped helicopter.

When two suspicious plane accidents occur near an eastern airport, the two Hardy brothers investigate the case and find themselves in greater danger than they anticipated.

A chance meeting with a stranger on the road provides the Hardy brothers with a clue to a gang of local burglars.

Frank and Joe are in London and learn that a new voice transmitter that can be implanted in a tooth has been stolen.

When the Hardy boys eagerly agree to assist their friend Jack Dodd and his father in locating a family treasure, the two young detectives are unaware of the baffling complications that will arise. The only clue to the long-lost treasure is a cryptic message written by a Pilgrim ancestor. But when Mr. Dodd and Jack are accused of stealing cars and then mysteriously disappear, Frank and Joe are confronted with a triple mystery. Have their friends run...

Extremists may resort to drastic measures to protect the environment, but did they really threaten the owner of a mall?

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