The Sword Thief by Peter Lerangis
Amy and Dan are headed to Japan with the lead to their third clue. Their Uncle Alistair knows the Japanese language and secrets about the country, so they form an alliance with him. The only problem is Uncle Alistair is less than trustworthy. Will he help them or betray them?
"With a secret of this much power, jealousies are inevitable and no alliances will survive."
Visit http://www.the39clues.com/ to continue the search for the clues.