The summer of 1960 was the hottest ever for Summit, Wisconsin. For kids seeking relief from the heat, there was a creek, sprinklers, and ice cream. But for Frankie, Viv, and Biz, it would be remembered as the summer evil paid a visit to their small town. With a to-do list in hand, the girls set forth to make their mark on that summer, but when three patients escape from Broadhurst Mental Institution, their idyllic lives take a sinister turn. Determined to uncover long-held secrets, the girls have no idea that what they discover could cost them their lives and the ones they hold dear.