Napoleon Xylophone hates his name, that’s why his friend calls him Zam. His life is about to change when his grandfather is abducted by a supernatural being. Zam doesn’t let his walking disability get in the way of fighting the changelings, wytes and gargoyles that come to life in the Underworld beneath Newcastle where his grandfather is held against his will. Not when he has a ghost for a friend, a wheelchair that thinks it's a changeling, and a grandfather who created a new life form that allows whoever wears it to speak to Time.