The Secret Panel

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

Another exciting mystery begins for Frank and Joe when they help a stranger who has had an accident with his car. The man introduces himself as John Mead, owner of a nearby estate. But when the Hardy boys find an odd-looking house key and try to return it, they realize that John Mead died five years ago! They are even more amazed when they find that the intricately carved doors in the deserted mansion have no visible knobs or keylocks. What happens when Frank and Joe discover that there is a link between their father’s case of thieves and the mysterious Mead mansion will keep the reader on edge with thrills and suspense.

Strange events involve Frank and Joe Hardy in a mystery which shrouds an ancient treasure—the golden head of the Pharaoh Rhamaton IV. The owner of the million-dollar golden Pharaoh’s head claims it was aboard the freighter Katawa, which sank not far from Whalebone Island. But suspicious developments indicate that Mehmet Zufar may be trying to defraud the shipping line’s insurance company. Frank and Joe enthusiastically accept the challenge of their famous detective father to assist him in investigating the complex case for Transmarine Underwriters.

When a crime syndicate takes over Bayport's reservoir Frank and Joe Hardy help their detective father solve the sinister mystery.

Louise and Jean become enmeshed in another mystery when they chance to meet Mrs. Zerbe, who used to work for Mr. Warrington, one of the owners of Captain Dana's ship. Mrs. Zerbe is devastated that she lost her job at Mr. Warrington's estate. During her conversation with the Danas, Mrs. Zerbe mentions a secret which she has kept for Mr. Warrington.