Legendary literary game-maker Garrison Griswold is back in action - this time with Unlock the Rock, an extravaganza on Alcatraz Island. But just as the fun starts to take off for Emily and James, important items from Griswold's game begin to disappear, and someone is framing Emily's brother Matthew as the criminal. As the friends jump from one clue to the next, they discover a web of connections between the stolen items and a tragic nineteenth century mystery involving Harriet Beecher Stowe. This new historic enigma is irresistible, but it might be impossible to decipher. And with Matthew's record on the line, Emily and James can't afford to leave this mystery uncracked.