The Sword of the Lady (Emberverse #6)

The "New York Times" bestselling author continues his "epic of survival and rebirth" ("Library Journal"), chronicling a modern world without technology.
Rudi Mackenzie has journeyed far across the land that was once the United States of America, hoping to find the source of the world-altering event that has come to be known as The Change. His final destination is Nantucket, an island overrun with forest, inhabited by a mere two hundred people who claim to have been transported there from out of time.
Only one odd stone house remains standing. Within it, Rudi finds a beautifully made sword waiting for him-and once he takes it up, nothing will ever be the same...