Fourteen-year-old Amy Cahill and her younger brother Dan thought they could return to their regular lives when they found the 39 clues. But the Vespers, powerful enemies, will stop at nothing to get the clues. And with the Vespers rising, the world is in jeopardy.
Amy and Dan Cahill's quest to find the million dollars takes them to Vienna, where they must outwit their power-hungry relatives as they seek to solve a clue involving Mozart.
When Amy and Dan Cahill's quest to find the million dollars takes them to Japan, they must decide whether or not to enter into an alliance with their uncle, Alastair Oh, whose motives for helping them are extremely questionable.
Amy and Dan Cahill learn an ultimate truth that reveals the Madrigal Mission's importance and the danger that their nefarious family members pose to the entire world.