Anonymous letters begin to arrive at several well-chosen residences. A valuable Vermeer is stolen. "Pentominoes" seem to provide the clues to the puzzle. A beloved teacher may be implicated. Petra and Calder, an unlikely team, set about to solve the mystery of how all of these things may be connected. Suddenly time is short, as the thief may be about to destroy this priceless work of art! 300 pages Ages 9-12