Kat Lightfoot thought that getting a job at the famed Tiffany's store in New York would be the end to her problems - she has money, new friends, and there's even an inventor working there who develops new weapons from clockwork, and who cuts diamonds with a strange powered ight. This is 1862, after all, and such thngs are the wonder of the age. But then events take a turn for the worse: men and women wander the streets talking of 'the darkness'; bodies vanish from morgues across town; and random, bloody attacks on innocent people take place in broad daylight. Soon Kat and her friends are fighting for their lives against a horde of infected people, with only their wits and ingenuity to help them.