The famous young detectives Frank and Joe Hardy are caught up in a dangerous web of intrigue when they agree to help Greg Woodson search for his grandfather’s missing will. When Henry Kurt, the temporary headmaster of Woodson Academy, insists that he is to inherit the property from Greg’s grandfather, the case becomes even trickier. Frank and Joe must risk their lives several times before they solve the mystery of Yellow Feather and trap a sinister criminal who will stop at nothing--even murder--to satisfy his greed for money.

The young detectives receive a trained peregrine falcon as a gift that involves them in an exciting mystery. Imagine their astonishment when the swift-flying falcon brings down a homing pigeon carrying two precious rubies! Startling events that ensue indicate the gems are a ransom that has been paid for the release of a kidnapped student from India, who had come to the United States to complete his education. But Tava, the son of a wealthy industrialist, is still being held captive. Hoping to find a clue to Tava’s whereabouts, the Hardys try to track down the owner of the ruby-bearing pigeon. Their every move, however, is thwarted by the dangerous criminals not only involved in the kidnapping, but also in the large-scale smuggling of aliens from India to the United States. How Frank and Joe eventually outwit their adversaries climaxes this thrill-packed mystery adventure.

When thieves hijack a collection of stuffed animals from a country auction, Frank and Joe Hardy pursue the getaway car and are drawn into a thrilling mystery. At the same time, the young detectives’ father—famed private investigator Fenton Hardy—is tracking down an industrial spy ring. This suspense-filled story of pursuit and detection will keep the reader breathlessly following the chain of unexpected developments that lead Frank and Joe to the spine-tingling climax in the wilds of Northern Canada.

The Canadian Northwest beckons Frank and Joe Hardy to mystery and adventure. It all starts when a French-Canadian trapper, Caribou Caron, makes a historical and valuable find–-a carved rune stone left by Vikings centuries ago near Great Slave Lake. When Caribou Caron attempts to sell the artifact to a representative of a museum, it is snatched by thieves. Like the intrepid Vikings of old, Frank and Joe, with their close pal Chet Morton, set off on a perilous quest in the Northwest Territories to recover the valuable artifact before the robbers can decipher the symbols leading to the buried treasure.

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.

One exciting event follows another when Frank and Joe Hardy are hired to apprehend the pickpockets who have been plaguing Solo’s Super Carnival. When their friends Tony Prito and Biff Hooper exhibit a stuffed whale dug up at a construction project, they all but put the carnival out of business. In this thrilling mystery the young detectives pit their wits against a gang of thieves whose bizarre identification, a three-part whale tattoo, proves to be a nearly insolvable riddle.

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.

The Hardys purchase a Chinese junk to use as a ferry service, in order to make some money over the summer. It soon becomes apparent that others are very interested in the ship.

A sleek new hydrofoil is scheduled to start ferrying passengers between Bayport and Cape Cutlass. But business enemies of the hydrofoil owner have stirred up a hornets’ nest of violent opposition among small boat owners. Fearing sabotage, he begs Frank and Joe Hardy to guard the Flying Express on her maiden trip. Startling developments plunge the teenage detectives into a dangerous chase by sea, air, and land in pursuit of a gang of hardened criminals who operate by the signs of the Zodiac. Tension mounts when the Flying Express vanishes – and so does Sam Radley, Mr. Hardy’s skilled operative. Peril stalks Frank and Joe’s every moves as they hunt down the terrifying gangleader Zodiac Zig and his vicious henchmen.