Mattie and Gemma, two little sisters, find themselves spending the whole summer at their grandparents' home in the country. Discovering their great-great-great-grandpappy's journal, the girls set out on a course of mystery and adventure. Needing help from the only kids around, the girls decide to enlist the Gonker twins who live down the road from Grandma and Grandpa to help them. Nathan and Nick are two spoiled brats that pick on girls whenever they get the chance. Knowing this, Mattie and Gemma take on disguises to fool the boys. Staying a step ahead of the boys, the girls try to find what Grandpa never could. These two little girls will make you laugh and may bring you to tears, but they will always keep you wondering what they are up to next.