The Castle Conundrum

The Castle Conundrum is a Hardy Boys novel. It was first published in 2001.^[1]

The Hardys head to France to help in the construction of a center for children, thanks to Teen Village International, a worldwide, non-profit organization. But the Hardys soon realize that the castle next door is supposedly haunted. The Hardys soon realize that someone is after the treasure hidden inside the castle, and now, the Hardys must find out who, before he or she gets rid of them for good.

References

↑ The Castle Conundrum at Fantastic Fiction

The Hardy Boys

Series

Original	The Tower Treasure The House on the Cliff The Secret of the Old Mill The Missing Chums Hunting for Hidden Gold The Shore Road Mystery The Secret of the Caves The Mystery of Cabin Island The Great Airport Mystery What Happened at Midnight While the Clock Ticked Footprints under the Window The Mark on the Door The Hidden Harbor Mystery The Sinister Signpost A Figure in Hiding The Secret Warning The Twisted Claw The Disappearing Floor Mystery of the Flying Express The Clue of the Broken Blade The Flickering Torch Mystery The Melted Coins The Short-Wave Mystery The Secret Panel The Phantom Freighter The Secret of Skull Mountain The Sign of the Crooked Arrow The Secret of the Lost Tunnel The Wailing Siren Mystery The Secret of Wildcat Swamp The Crisscross Shadow The Yellow Feather Mystery The Hooded Hawk Mystery The Clue in the Embers The Secret of Pirates' Hill The Ghost at Skeleton Rock The Mystery at Devil's Paw The Mystery of the Chinese Junk Mystery of the Desert Giant The Clue of the Screeching Owl The Viking Symbol Mystery The Mystery of the Aztec Warrior The Haunted Fort The Mystery of the Spiral Bridge The Secret Agent on Flight 101 Mystery of the Whale Tattoo The Arctic Patrol Mystery The Bombay Boomerang Danger on Vampire Trail The Masked Monkey The Shattered Helmet The Clue of the Hissing Serpent The Mysterious Caravan The Witchmaster's Key The Jungle Pyramid The Firebird Rocket The Sting of the Scorpion

Digest	Night of the Werewolf Mystery of the Samurai Sword The Pentagon Spy The Apeman's Secret The Mummy Case Mystery of Smugglers Cove The Stone Idol The Vanishing Thieves The Outlaw's Silver The Submarine Caper (retitled Deadly Chase) The Four-Headed Dragon The Infinity Clue Track of the Zombie The Voodoo Plot The Billion Dollar Ransom Tic-Tac-Terror Trapped at Sea Game Plan for Disaster The Crimson Flame The Skyfire Puzzle Cast of Criminals Fear on Wheels Day of the Dinosaur Crime in the Kennel Cross-Country Crime The Search for the Snow Leopard Eye on Crime The Caribbean Cruise Caper The Hunt for the Four Brothers A Will to Survive Daredevils A Game Called Chaos Training for Trouble The End of the Trail Skin & Bones Crime in the Cards Past And Present Danger Trouble Times Two The Castle Conundrum In Plane Sight Passport to Danger Warehouse Rumble The Dangerous Transmission

Casefiles	Dead on Target Evil, Inc. Cult of Crime See No Evil Perfect Getaway Street Spies Running on Empty River Rats

Undercover Brothers	Extreme Danger Running On Fumes Boardwalk Bust Operation: Survival Top Ten Ways to Die Martial Law Blown Away Hurricane Joe Trouble in Paradise The Mummy's Curse Hazed Death And Diamonds Bayport Buccaneers Murder At The Mall Pushed Foul Play Feeding Frenzy Comic Con Artist Deprivation House (Murder House trilogy) Murder House Double Trouble (Double Trouble trilogy) Galaxy X (Galaxy X trilogy) The Children of the Lost (Lost Mystery trilogy)

Crossovers

Authors

Characters

Frank Hardy
Joe Hardy
Fenton Hardy
Laura Hardy
Vanessa Bender
Phil Cohen
Chief Ezra Collig
Belinda Conrad
Brian Conrad
The Gray Man
Aunt Gertrude
Biff Hooper
Chet Morton
Iola Morton
Tony Prito
Callie Shaw

Locations

Organizations

American Teens Against Crime
The Assassins
MUX
The Network
Warring Adolescents Revenge Division