 Sixth @-@ <unk> Calder Pillay , who enjoys puzzles and pentominoes , and Petra Andalee , who <unk> to be a writer , are classmates at the Middle School in Hyde Park , Chicago . Their young teacher , Ms. Hussey , is very interested in art and teaches them in a creative way . Through her pressing questions , they discover the artist Johannes Vermeer and his paintings , especially A Lady Writing and The <unk> . Petra also finds a used book called Lo ! , written by Charles Fort , at the local Powell 's Books , owned by a man named Mr. Watch . They also meet an elderly neighbor , Mrs. Sharpe , who is also a fan of Vermeer and Fort . Calder receives letters from his best friend Tommy <unk> , who is currently living in New York City with a new stepfather . 
