—Leadership is the ability to convince followers to fight and die to enhance the leader's wealth and power.

A disastrous encounter with the Danes injures Roger Martel, a Carolingian knight, and strands him on the western shore of Britannia. As a result of his leaders' incompetence, he loses faith in Kings, Emperors, and other great Lairds and resolves never to return to the Carolingian Empire. After he recovers, he tracks east, instead, to find his old battle companion Drogo. He finds Drogo in the Valley of Strathnith where the old knight has taken up the defense of a small community against Viking invaders. Never one to avoid a fight, Roger joins them and soon finds himself accepted as the leader. Reluctantly, he takes the job while telling himself that he does so only to protect his friends, not become a great Laird himself. Unfortunately, wealth and power are seductive.

"Plus que nous avons, plus que nous voulons. The more we have, the more we want."—Roger Martel

Marked by Thor is a Rogue Knight alternate history adventure that takes place in 816, two years after the death of Charlemagne.