The Books
X Marks the Spot, by Brian Thomas
60 adventures. Each book comes in an Easy or Hard edition, and the first four come in both. All coming soon.
Book 1The Square KeyEasy · Hard 
Book 2The Mountain PassEasy · Hard 
Book 3The Hidden TunnelEasy · Hard 
Book 4The Sharkwater BellEasy · Hard 
Book 5The Nameless WellHard 
Book 6The Silent FlightHard 
Book 7The Rainforest CipherHard 
Book 8The Midnight TableHard 
Book 9The Clockwork CarnivalEasy 
Book 10The Lighthouse SecretEasy 
Book 11The Space Camp SignalEasy 
Book 12The Treehouse CodeEasy 
Book 13The Snowglobe VillageEasy 
Book 14The Dinosaur DigEasy 
Book 15Zoo After DarkHard 
Book 16The Clockmaker's AtticEasy 
Book 17The Riverboat RiddleEasy 
Book 18The Candy Factory KeyEasy 
Book 19The Observatory GhostHard 
Book 20The Canal LockEasy 
Book 21The Cartographer's VaultHard 
Book 22The Tide MarkerHard 
Book 23The Silent FrequencyHard 
Book 24The Torn ManualEasy 
Book 25The Harvest QuiltEasy 
Book 26The Mirror PressHard 
Book 27The Juniper LineEasy 
Book 28The Market Scale MysteryEasy 
Book 29The Sandcastle CrownEasy 
Book 30The Crooked WeathervaneEasy 
Book 31The Miniature MuseumEasy 
Book 32The Marionette's Missing ActHard 
Book 33The Glasshouse BloomEasy 
Book 34The Echo CavernsHard 
Book 35The Kite Festival CodeEasy 
Book 36The Octopus PuzzleEasy 
Book 37The Geyser TimetableHard 
Book 38The Starlight RocketEasy 
Book 39The Hot-Air Balloon HuntEasy 
Book 40The Organ Pipe PuzzleHard 
Book 41The Seven Castle FlagsEasy 
Book 42The Honeycomb CodeEasy 
Book 43The Ice Station MessageHard 
Book 44The Bookmobile TrailEasy 
Book 45The Hedge MazeHard 
Book 46The Cable Car ClueEasy 
Book 47The Firehouse MedalEasy 
Book 48The Ninety-Ninth FloorHard 
Book 49The Post Office PuzzleEasy 
Book 50The Giant ChessboardHard 
Book 51The Friendship ParadeEasy 
Book 52The Big Top BannerEasy 
Book 53The Crater BoardwalkHard 
Book 54The Painted FigureheadEasy 
Book 55The Robot RallyEasy 
Book 56The Submarine HatchHard 
Book 57The Carousel HorseEasy 
Book 58The Windmill SailsEasy 
Book 59The Backlot WindowHard 
Book 60The Figure EightEasy