Carl Streator, a reporter investigating Sudden Infant Death Syndrome, discovers a horrifying pattern: all the victims were read the same poem from the same library book. The poem is a 'culling song'—an ancient African spell for euthanasia. When he learns he accidentally killed his own wife and child with it years ago, he teams up with another grieving parent to hunt down and destroy every copy of the book. Darkly comedic and deeply tragic, Lullaby follows two damaged people on a desperate mission to contain an unstoppable evil—while trying not to kill everyone who stands in their way.