Lillian and Madison were the unlikeliest of roommates at their elite boarding school: Madison, the daughter of a prominent Atlanta family, being groomed for greatness; Lillian, a scholarship student, plucked out of nowhere based solely on her intellect and athletic prowess. The two were as tight as could be, reveling in their unique weirdnesses, until Lillian had to leave the school unexpectedly. Years later, the two have lost touch, but Madison writes and begs Lillian for help. Her husband's twin stepkids are moving in with them and she wants Lillian to be their caretaker. However, there's a catch: the twins can spontaneously combust when they get agitated, flames igniting from their skin in a disturbing but beautiful way. Disbelieving at first but ultimately too intrigued by these strange children, Lillian agrees. And as they hunker down in the pool house, Lillian and the twins learn to trust each other--and stay cool--just as Madison's family is bracing for a major announcement. It all seems impossible to manage, but Lillian soon accepts that she and the children need each other, urgently and fiercely.