Twelve-year-old Pete Collison is a regular kid who loves Sam Spade detective books and radio crime dramas, but when an FBI agent shows up at Petes doorstep accusing his father of being a Communist, Pete finds himself caught in a real-life mystery. Could there really be Commies in Petes family? At the same time, Petes class turns against him, thanks to similar rumors spread by his own teacher; even Kat, Petes best friend, feels the pressure to ditch him. As Pete follows the quickly accumulating clues, he begins to wonder if the truth could put his familys livelihood–and even their freedom at risk.