While attending a thing (an assembly), the hero's close-knit group learns that a wise man named Gest has predicted discord among them (the "Haukdal men") in three years. To forestall this, Gisli, Thorkel, Thorgrim (brother-in-law to both), and Vestein (Gisli's brothers-in-law) decide to enter a pact of blood brotherhood (Fóstbræðralag, "foster brotherhood"). However, Thorgrim has a change of heart and the pact is not completed. From this moment on the characters’ actions seem to be largely controlled by fate as they head down a tragic path.