This first one, "The Tower Mystery," introduced the action, mystery, and suspense themes. The boys continue to deliver thrills to this day.It all starts with the boys, Frank and Joe, on their motorcycles delivering important papers to a lawyer in Willowville for their father, Fenton Hardy. He's the well-known private investigator in Bayport. A reckless driver almost forces them over the embankment. It is not long before they find that their friend Chet's yellow jalopy has been stolen, possibly by the same red-haired driver! Stolen loot may be the issue. Later a dying criminal confesses that the loot has been stashed "in the tower" and the Hardy Boys make an astonishing discovery.

    But then a millionaire's daughter moves into the next-door mansion, an old miser hides a fortune in his decrepit house, and a runaway kid starts hiding out in Sleepyside!"

    It's snowing and the Seven are dressed in disguise, following a lead to a spooky old house - and a mystery.

    But when the boys arrive for an overnight visit at Terror Castle -- home of a deceased horror-movie actor -- they soon find out how the place got its name!

    Or at least her shoes are. And getting them back will mean getting tangled up in a murder investigation as complicated as the mysteries solved by her idol, Sherlock Holmes. With soccer practice, schoolwork, and the lead role in her town's production of Alice in Wonderland, Ingrid is swamped. But as things in Echo Falls keep getting curiouser and curiouser, Ingrid realizes she must solve the murder on her own -- before it's too late!

    Her knowledge of English literature, French, history, art and music is non-existent, but she has a thorough grounding in military tactics, can run a business, ride like a Cossack and shoot straight with a pistol.When her dear father is drowned in suspicious circumstances in the South China Sea, Sally is left to fend for herself, an orphan and alone in the smoky fog of Victorian London. Though she doesn't know it, Sally is already in terrible danger. Soon the mystery and the danger will deepen - and at the rotten heart of it all lies the deadly secret of the ruby in the smoke...

    Marden reports that some of her valuables have gone missing, the twins investigate.

    She knows that little girl is she. But how could it be true?Janie can't believe that her loving parents kidnapped her, until she begins to piece together clues that don't make sense. Why are there no pictures of Janie before she was four? Her parents have always said they didn't have a camera. Now that explanation sounds feeble. Something is terribly wrong, and Janie is afraid to find out what happened more than twelve years ago.In this gripping page-turner, the reader will unravel—as Janie does—the twisted events that changed the lives of two families forever.

    Mandie's move into a neighbor family's home, when her mother remarries, does not soften her grief. Her only comfort is the promise from her father's faithful Cherokee friend, Uncle Ned, to watch out for her and be a friend. Will Mandie be able to escape her new and nearly intolerable home situation? Will she find her long-lost family? Will the mysterious key unlock the door to the secret tunnel and her own family's history?For children 8-13, mystery adventures set in the North Carolina backwoods at the turn of the century.

    Locals claim that inside a dark cavern called the Dragon's Throat is a forbidden Door that brings certain death to anyone who tries to open it.Armed with the knowledge that God is more powerful than any legend or curse, Jay and Lila plunge down into the Dragon's Throat, determined to find out what awaits them on the other side of the Door. This daring tale will have you on the edge of your seat.

    Try to crack the cases along with him--the answer to all the mysteries are found in the back!

    Now Sammy's witnessed a crime at the Heavenly Hotel-a light fingered thief stealing $4,000 from Madame Nashira, the astrologer with the fire-hazard hair-do. Thing is, while she was watching him, he was watching her, too...Fast-paced and funny, packed with menacing suspects and clever clues, the Sammy Keyes mysteries keep you guessing to the last riveting page.

    Stacey would never take anything from anyone!Even worse for the Baby-sitters, the Gardellas are threatening to tell their other clients about the missing ring.Will everyone in Stoneybrook think the Baby-sitters are stealers? Not if Stacey can help it. She's going to find out what happened to that ring!

    Before they know it, the two find themselves at the center of an international art scandal, where no one — neighbors, parents, teachers — is spared from suspicion. As Petra and Calder are drawn clue by clue into a mysterious labyrinth, they must draw on their powers of intuition, their problem-solving skills, and their knowledge of Vermeer. Can they decipher a crime that has left even the FBI baffled?

    These suspenseful stories will leave readers on the edge of their seats! Each spine-tingling tale features a brave, clever girl solving an intriguing mystery at an important time in America's past.Elisabet comes face to face with a famous pirate when she tries to free her father, who is a prisoner in the War of 1812.