Dan and Amy continue the hunt for clues as they travel to Japan and explore and ancient ways of the samurai, but are soon separated from Nellie, the children's au pair, and reluctantly agree to partner with a Cahill relative in hopes of strength in their combined expertises. But wait, is Amy actually starting to fall for the enemy? And can Dan and Amy trust one another enough to solve the clues and avoid getting killed? The adventure builds in the third installment in the 39 Clues series, where no one can be trusted and nothing works out as expected.