During a violent thunderstorm, an unexplained phenomenon transports the titular 20th-century American US Army MP back in time to Ospak's homestead.
The American, who becomes known as Gerald "Samsson", is an engineering student drafted to serve at Keflavik during the Cold War between the U.S. and the Soviet Union.
Knowledge of 20th-century metallurgy does not endow him with the highly specialised skill needed to work in a 10th-century smithy, and his attempt to do so ends with a costly fiasco.
And conversely, when Gerald tells that he had been a military policeman and describes the task of one, they are astonished at what they see as his foolhardy courage of "offending all the men in the war host" - since Vikings would absolutely not have tolerated the petty regulation of their dress and personal life which is common for soldiers in a 20th-century army.
[5] Black Gate considers it "first rate",[6] while Paul A. Carter states that, as a "tale of the modern man displaced in time to a harsh and unforgiving environment which dooms him", it is "more sophisticated" than Nat Schachner's "Master Gerald of Cambray".