When the four Haskell grandchildren from Sioux Falls, South Dakota, visit their grandparents' country farm for the summer, they're convinced that spending time in rural Aberdeen is going to be totally boring. But for Audrey, a responsible twelve-year-old, defiant eleven-year-old twins Denny and Jenny, and Ty, an enthusiastic seven-year-old, their days of adventure are just beginning. To fill their time, the children start a club-the secret Peanut Butter Club-and their first order of business is to investigate a local crime spree. Something, or someone, is killing the deer down by the James River. Turning an ordinary fishing trip with Grandpa into a chance to investigate this baffling mystery, Audrey, Jenny, Denny, and Ty look for clues and build a case that could help Sheriff Whippert solve the mystery. By working together and relying on each other, the Thomsen kids learn about true friendship, responsibility, and how to have fun in an old-fashioned way, while creating lasting memories with their grandparents.