While on vacation, divorced Philadelphia art therapist Zoe Hayes decides to take a sculling class on the Schuylkill River with her best friend, Susan - just for fun. One evening, while their children watch from the riverbank, Zoe rows off with Susan to practice for an upcoming regatta...When Susan's oar catches on some flotsam (which turns out to be a woman's dress), the boat flips, and the two friends find themselves in deep waters with not just one but an entire throng of floating bodies. Someone along Boathouse Row is a murderer, but who could it be? After Zoe argues with the enigmatic Detective Nick Stiles, who happens to be her boyfriend, she and Molly head out to the river at night in search of clues. There, Zoe uncovers a sinister plot that she and Molly might not be able to stop...or escape.