For centuries, the Vikings have swept out of the Norse countries and fallen on whatever lands they could reach aboard their longships, and few could resist the power of their violent onslaught. They came at first to plunder and then to settle, an encroachment fiercely resisted wherever they went. Such was the case in the southern lands of Ireland. En route to the Viking longphort there, known as Dubh-linn, Thorgrim Night Wolf and Ornolf the Restless stumble across an Irish ship.
With their ill-fated raid on the monastary at Glendalough torn apart by betrayal and defeat, Thorgrim Night Wolf and his handful of survivors from the crew of Sea Hammer find themselves in desperate and tenuous straits. Stranded far from the safety of Vik-lo, surrounded by enemies, and with barely enough men to work the longship's oars, the Norsemen must make their way back through a dangerous and uncertain country. Thorgrim, however, is not interested in mere survival. His one thought, his one desire, is to take revenge.
"I hope it's not the last one."
Spring has come to Ireland, where Thorgrim Night Wolf, new-made Lord of Vík-ló, and the 300 Viking warriors under his command have suffered through a brutal winter. Despite having accomplished much during the months of cold and rain, the patience of the men has worn thin, and anger and frustration threaten to tear the ships' crews apart. But just as the men are turning on one another, a local Irish lord arrives with a proposal, a plan for Irish and Norse to join together in a raid.
Eager to return to his native Norway, Thorgrim agrees to participate in one last raid under the command of a man he does not trust. But the Northmen, he finds, are no longer simply invaders on foreign soil. They have become a part of the Irish kings' ongoing struggle for power, and, far from securing a means to return home, Thorgrim and his men are plunged into a battle for the throne of Tara - a battle that will test their strength and loyalty as none has before.
Having recovered from the wounds of battle and having won for himself a fortune, a crew, and a longship, Thorgrim Night Wolf makes ready to leave the Viking town of Dubh-linn for the long journey back to his home in Norway. But the gods have other plans, and Thorgrim and his men wash up in the small Viking longphort of Vík-ló. Thinking themselves among friends, they soon learn that the opposite is true - that Grimarr Giant, the Lord of Vík-ló, has reason to want Thorgrim and his son, Harald, dead.