Young William Bonney is talked into committing his first train robbery, unaware that his cousin and best friend, Willie Monroe, is now sheriff of the nearest town, and that his fellow robbers are already wanted in four states.

Whatever his name or alias at the moment-Henry McCarty, Henry Antrim, Kid Antrim, Billy Bonney-people always called him the Kid. Not until his final month did anyone call him Billy the Kid. Newspapers pictured him as a king of outlaws; and his highly publicized capture, trial, escape, and end fixed his image in the public mind for all time. He was only twenty-one years old when a bullet from Sheriff Pat Garetts six-shooter killed him on July 14, 1881....

Fifteen-year-old Josh has chosen to side neither with his twin sister Sophie nor with the Alchemyst, Nicholas Flamel, but rather to fight alongside Dr. John Dee and the mysterious Virginia Dare, while the immortal Machiavelli and Billy the Kid follow the Elders' plans to set loose the monsters of Alcatraz on San Francisco and trigger the end of the humani race.