The Treasure in the Royal Tower (1980)
by Carolyn Keene
(#128 in Nancy Drew Mystery Stories)

The Secret of the Old Clock

The Hidden Staircase

The Bungalow Mystery

The Mystery at Lilac Inn

The Secret of Shadow Ranch

The Secret of Red Gate Farm

The Clue in the Diary

Nancy&#039;s Mysterious Letter

The Sign of the Twisted Candles

Password to Larkspur Lane

The Clue of the Broken Locket

The Message in the Hollow Oak

Mystery of the Ivory Charm

The Whispering Statue

The Haunted Bridge

The Clue of the Tapping Heels

The Mystery of the Brass-Bound Trunk

The Mystery at the Moss-covered Mansion

The Quest of the Missing Map

The Clue in the Jewel Box

The Secret in the Old Attic

The Clue in the Crumbling Wall

Mystery of the Tolling Bell

The Clue in the Old Album

The Ghost of Blackwood Hall

The Clue of the Leaning Chimney

The Secret of the Wooden Lady

The Clue of the Black Keys

Mystery at the Ski Jump

The Clue of the Velvet Mask

The Ringmaster&#039;s Secret

The Scarlet Slipper Mystery

The Witch Tree Symbol

The Hidden Window Mystery

The Haunted Showboat

The Secret of the Golden Pavilion

The Clue in the Old Stagecoach

The Mystery of the Fire Dragon

The Clue of the Dancing Puppet

The Moonstone Castle Mystery

The Clue of the Whistling Bagpipes

The Phantom of Pine Hill

The Mystery of the 99 Steps

The Clue in the Crossword Cipher

The Spider Sapphire Mystery

The Invisible Intruder

The Mysterious Mannequin

The Crooked Banister

The Secret of Mirror Bay

The Double Jinx Mystery

Mystery of the Glowing Eye

The Secret of the Forgotten City

The Sky Phantom

The Strange Message in the Parchment

Mystery of Crocodile Island

The Thirteenth Pearl

The Triple Hoax

The Flying Saucer Mystery

The Secret in the Old Lace

The Greek Symbol Mystery

The Swami&#039;s Ring

The Kachina Doll Mystery

The Twin Dilemma

Captive Witness

Mystery of the Winged Lion

Race Against Time

The Sinister Omen

The Elusive Heiress

Clue in the Ancient Disguise

The Broken Anchor

The Silver Cobweb

The Haunted Carousel

Enemy Match

The Mysterious Image

The Emerald-Eyed Cat Mystery

The Eskimo&#039;s Secret

The Bluebeard Room

The Phantom of Venice

The Double Horror of Fenley Place

The Case of the Disappearing Diamonds

The Mardi Gras Mystery

The Clue in the Camera

The Case of the Vanishing Veil

The Joker&#039;s Revenge

The Secret of Shady Glen

The Mystery of Misty Canyon

The Case of the Rising Star

The Search for Cindy Austin

The Case of the Disappearing Deejay

The Puzzle at Pineview School

The Girl Who Couldn&#039;t Remember

The Ghost of Craven Cove

The Case of the Safecracker&#039;s Secret

The Picture Perfect Mystery

The Silent Suspect

The Case of the Photo Finish

The Mystery at Magnolia Mansion

The Haunting of Horse Island

The Secret at Seven Rocks

A Secret in Time

The Mystery of the Missing Millionairess

The Secret in the Dark

The Stranger in the Shadows

The Mystery of the Jade Tiger

The Clue in the Antique Trunk

The Case of the Artful Crime

The Legend of Miner&#039;s Creek

The Secret of the Tibetan Treasure

The Mystery of the Masked Rider

The Nutcracker Ballet Mystery

The Secret at Solaire

Crime in the Queen&#039;s Court

The Secret Lost at Sea

The Search for the Silver Persian

The Suspect in the Smoke

The Case of the Twin Teddy Bears

Mystery on the Menu

Trouble at Lake Tahoe

The Mystery of the Missing Mascot

The Case of the Floating Crime

The Fortune Teller&#039;s Secret

The Message in the Haunted Mansion

The Clue on the Silver Screen

The Secret of the Scarlet Hand

The Teen Model Mystery

The Riddle in the Rare Book

The Case of the Dangerous Solution

The Treasure in the Royal Tower

The Baby-Sitter Burglaries

The Sign of the Falcon

The Hidden Inheritance

The Fox Hunt Mystery

The Mystery at the Crystal Palace

The Secret of the Forgotten Cave

The Riddle of the Ruby Gazelle

The Wedding Day Mystery

In Search of the Black Rose

The Legend of the Lost Gold

The Secret of Candlelight Inn

The Door-to-Door Deception

The Wild Cat Crime

The Case of Capital Intrigue

Mystery on Maui

The E-Mail Mystery

The Missing Horse Mystery

The Ghost of the Lantern Lady

The Case of the Captured Queen

On the Trail of Trouble

The Clue of the Gold Doubloons

Mystery at Moorsea Manor

The Chocolate-Covered Contest

The Key in the Satin Pocket

Whispers in the Fog

The Legend of the Emerald Lady

The Mystery in Tornado Alley

The Secret in the Stars

The Music Festival Mystery

The Curse of the Black Cat

The Secret of the Fiery Chamber

The Clue on the Crystal Dove

Lost in the Everglades

The Case of the Lost Song

The Clues Challenge

The Mystery of the Mother Wolf

The Crime Lab Case

The Case of the Creative Crime

Mystery by Moonlight

The Bike Tour Mystery

The Mistletoe Mystery

No Strings Attached

Intrigue at the Grand Opera

The Riding Club Crime

Danger on the Great Lakes

A Taste of Danger

Werewolf in a Winter Wonderland