A Mutiny in Time / James Dashner / 190 pages

Book one of Infinity Ring series is very similar to the 39 Clues series in format as each book is written by a well-known children's author and there are accompanying online games and collectibles to complement each book.  After discovering a handheld device - The Infinity Ring - a key to time travel, Sera and Daq are recruited by the Hystorians to journey back in time to fix breaks in history and prevent the end-time cataclysm facing the world.  Mutiny on Columbus' ships is prevented.