What do you do when a crusader returns with devils on his back?

It is late autumn 1196. A secretive stranger arrives at New Winnowlands, and Sir Josse d'Acquin guesses that he is a returning Crusader. Josse allows him to put up in an outhouse, and seeks the assistance of Abbess Helewise of Hawkenlye to have his injuries treated in the infirmary. But then the various demons who are on the man's trail begin to turn up, and Josse realises that his mysterious guest has brought with him danger and a terrible secret.