Paper Valentine

Paper Valentine is a young adult novel by Brenna Yovanoff, published in 2013 and set in a town decorating itself for Valentine's Day while young girls are being killed.

Hannah is grieving for her best friend Lillian, who died months ago and has not entirely gone away: Lillian's ghost follows her through the town, offering opinions, and nobody else can see or hear her. At the same time somebody is murdering girls in the community, and the adults would prefer to treat the deaths as unrelated incidents. Hannah is close in age to the victims and the only person with a ghost for company, so she begins investigating what is happening, with the town's paper hearts and hand-made messages forming an incongruous background to the search. The evidence she gathers is difficult to discuss with anyone, because her best informant is invisible to everybody but her.

Yovanoff writes a ghost story in which the supernatural element is companionable and sad rather than simply frightening, and the plot leans on grief and guilt as much as on the killer.