Year One by Nora Roberts
It all begins with a family on vacation in Ireland. On their way back home to New York, the husband grows sick. By the next day, he's in the hospital, dying. The sickness spreads quickly-- worldwide. Governments collapse, mayhem reigns supreme. Only instead of a zombie apocalypse, people start seeing things out of fairy tales: people flying, unicorns in the street, monsters in the subways.