The residents of the new-ish "Active Adult" community in the Chicago suburban town of Deer Creek may all be over-55, but many of them are very active, indeed. Each has moved to Martingale Manor fairly recently, and they've all brought a lot of history with them, including plenty of secrets. Keeping too many secrets can be dangerous. Sometimes, one might even kill you.Bella Sarver knows a lot about art. In fact, she's been asked to teach a class in...