James Henry, a lovable librarian, has gotten used to being back home in Quincy's Gap, a tiny town in Virginia's Shenandoah Valley. He has a job he adores, a group of close friends and fellow dieters who call themselves the "Flab Five", and is actually thinking about starting an exercise regimen.

Six months after starting a low-carb diet, however, James and the Flab Five have fallen off the diet wagon. A new ice cream shop has opened in town, but so has the Witness to Fitness weight loss center, run by the zealous Veronica Levitt. Maybe Veronica's fanatical approach is just what the group needs.

But when James and his fellow dieters poke around in an arson case that turns into a murder investigation, the Flab Five discover that they may have bitten off more than they can chew. It isn't long before James wonders if he can handle cardio classes, a budding romance, his cranky father, and a duplicitous killer without binging on too ice cream.