Karla died in a fire. Now she's still in the World of the Living as a blue ghost and she is sure of two things. One: the fire was set and Two: she knows who set it. It was Valerie. Karla knows that Valerie set it intentionally, knowing harm would come to her, but she doesn't know why and she doesn't know how. She's determined to figure it out and not let Valerie get away with it, all while she gets her friends and family to move on. Getting them to move on should be easy, seeing as they're able to hear and feel her even while she's dead.