Lilian Campbell and her best friend and lover, Ada Strauss, are woken early by the sound of sirens: the local nursing home, Nillewaug Village, is ablaze. The police and fire chiefs find evidence to suggest the fire was accidental, but Detective Mattie Perez can’t help but wonder why the smoke alarms didn’t work. Soon, it’s looking less like accident and more like arson…and Lil and Ada are swept up into an investigation that grows increasingly more complex, and frightening, by the hour.