Gitta's best friend has a passion for playing detective. But the game turns deadly serious when a precious Stradivarius is stolen from the antiques store of Gitta's grandfather. Gitta is horrified and fearful, whereas Pompom is triumphant. At last, a real case - no more fooling around with make-belief! Her clever detective nose has sniffed out several suspects which leads her on a dangerous chase, ending in a dark, moldy cellar. Who is the thief: the Scarf Lady, Dapper Dan, the Gray Man, or perhaps even the kindly Herr Kadinsky? Pompom is determined to find out. Besides being a fun book of lively entertainment, it is also a story of growing and growing up.