My Swordhand Is Singing — Marcus Sedgwick

WHEN TOMAS AND HIS SON, Peter, settle in Chust as woodcutters, Tomas digs a channel of fast-flowing waters around their hut, so they have their own little island kingdom. Peter doesn't understand why his father has done this, nor why his father carries a long, battered box, whose mysterious contents he is forbidden to know.

But Tomas is a man with a past: a past that is tracking him with deadly intent, and when the dead of Chust begin to rise from their graves, both father and son must face a soulless enemy and a terrifying destiny.