The Bloodstained Throne by Simon Beaufort

The new 'Sir Geoffrey Mappestone' mystery - When the former crusader knight Geoffrey Mappestone and his friend Roger of Durham try to slip out of England to the Holy Land, a ferocious storm destroys the ship they are on and casts them ashore. The two knights are unwillingly thrust into the company of other shipwrecked passengers, and while attempting to evade the unwelcome attention of the more dangerous members of the group, they become unwillingly drawn into a plot to overthrow the king and return England to Saxon rule . . .