Harley James, explorer and amateur cryptologist, has just arrived in Port Royal, Jamaica-home to the Caribbean's famous sunken pirate city. Her latest mission? Prevent a mysterious, mythical blue pearl from being discovered and prevent city's total destruction.

No sweat for an adventurer like Harley, right?

But just when Harley thinks she's on the right track, everything she believes is turned upside-down. Her friends become enemies; her enemies become friends; and Harley isn't sure who to trust-including the ghost who's started following her around.

With time running out, Harley must rely on her codebreaking expertise to discover the truth, solve the riddles, and save the city from certain disaster!