Possession — Chris Humphreys

RUNE MAGIC, TIME travel, transformation: Sky's grandfather opened up a world of limitless possibility . . . then asked the impossible. He asked Sky to kill a man.
Sky and Kristin know they have to stop Sigurd. But how, when he can possess any person, any beast, at will? Once more, the answer is to be found back along the bloodlines. The secret of possession lies in Meg, an accused witch, and in Matthew, the Witchfinder determined to capture her. But the price for knowing what Sigurd knows is steep--to defeat their grandfather, will they have to become exactly like him?
In this thrilling conclusion to the Runestone Saga, the final choice between everlasting life and the necessity of death will be made at one of the great turning points in history--a battle, quite literally, for all time. And the outcome rests precariously on one final cast of the runes. . . .