Brenna Yavanoff’s Paper Valentine is an intriguing mixed-category book: part ghost story and part murder mystery. Someone is killing young girls in Hannah’s suburban town of Ludlow, and Hannah feels compelled to solve the case because the ghost of her dead friend Lillian keeps pestering her to find out who it is before they kill again. When I first started reading, I thought that Hannah’s ghost friend would be one of the murdered girls. So I was troubled to learn that, like the ghost of Cassie in Laurie Halse Anderson’s Wintergirls, Lilian was the victim,[...]