Gertie Johnson may be outspoken, distrustful of banks, and a quick draw with the pepper spray, but she hasn't lost her marbles. Her son Blaze, the sheriff in a backwoods community of Michigan's Upper Peninsula, is petitioning to become her legal guardian, but Gertie, a sassy sixty-six-year-old widow with a taste for detective work, has got bigger fish to fry: solving the murder of Chester Lampi who was shot dead in his deer blind. Blaze-who's more interested in retiring than investigating-rules Chester's death as a hunting accident. So, Gertie takes on the case with help from her friends, man-hungry Cora Mae and pin-curled Kitty. Interrogating neighbors, spying, impersonating the FBI . . . the stubborn, spunky grandmother won't give up the chase even when the killer takes aim at her.