On the return from their pilgrimage to Santiago de Compostela, in the summer of 1323, Sir Baldwin de Furnshill and Bailiff Simon Puttock's ship is attacked by pirates. They fight their attackers off, but then there are too few shipmen when a terrible storm strikes. As the ship breaks up, Simon sees Baldwin washed overboard. Distraught, Simon makes his way to shore.
But on the island of Ennor, he must put aside his fears and investigate the murder of Robert, the island's hated tax collector, at the behest of master of the castle, Ranulph de Blancminster.
Meanwhile, washed up on the other side of the island, Baldwin begins his own investigation of the same murder. As the friends dig deeper, they become embroiled in a bitter rivalry between the two island communities. Can they uncover the truth in time to prevent certain massacre?