Whenever you hear the sky rumble, that usually means a storm. In Virgil Flowers's case, make that two. The first comes from, of all places, the Minnesota Zoo. Two large Siberian tigers have vanished from their cage, and authorities are very concerned that they've been stolen for their organs. Traditional Chinese medicine prizes their parts for home remedies, and people will do extreme things to get-- and keep-- what they need. As Virgil is about to find out. Then there's the home front. Virgil's relationship with his girlfriend, Frankie, has been getting kind of serious, but when Frankie's sister, Sparkle, moves in for the summer, things get a lot more complicated. Sparkle has a roving eye, and it's fixed right on Virgil. Forget a storm-- this one's a tornado.