Twelve-year-old Portia Maddox is thrilled to learn she has a sixteen-year-old sister, Jasmine. But from the moment Jasmine sets eyes on Portia, she does everything in her power to derail what she thinks is Portia's perfect life. Portia is desperate to stop the cruel pranks and to keep her diabetes a secret, for that would fuel the cruelest prank of all. Can Portia find a way to end the attacks, or even win Jasmine over?