Assigned as a reporter to do a series of articles on Sudden Infant Death Syndrome, Carl Streator makes an extraordinary discovery. After responding to several calls with paramedics, he notices that all the dead children were read the same poem from the same library book the night before they died.
It's a "culling song" - an ancient African spell for euthanising sick or old people. The song turns out to be lethal when spoken or even thought in anyone's direction - and once it lodges in Streator's brain he finds himself becoming an involuntary serial killer.
Researching it, he meets Helen, a woman who accidentally killed her own child with it twenty years ago. Together, they must find and destroy all copies of the book, and try not to kill every rude sonofabitch that gets in their way.
'Lullaby' is a comedy/drama/tragedy. In that order. It's also the best novel yet by an author whose following grows with every book.