Perpetual scaredy-cat Conor O'Neill has the fright of his life when a banshee girl named Ashling shows up in his bedroom. Ashling is, as all banshees are, a harbinger of death, but she's new at this banshee business, and first she insists on going to middle school. As Conor attempts to hide her identity from his teachers, he realizes he's going to have to pay a visit to the underworld if he wants to keep his family safe.