Below the surface of the North Sea is where most of the action in this story takes place, although it does begin and end in the Shetland Islands. The time is 1943 and the hero an English submarine named Setter which had been commissioned to make the dangerous journey to occupied Norway. There a Bishop who has been uncooperative towards the German overlords waits for his family to be taken to England. We follow the Setter as it makes its trip and safe return without ever doubting its ultimate success, although there are dangerous encounters and a little submarine anatomy to keep us entertained while a few rudimentary characters make conversation. Chief among these is Leif Olsen, regularly of the Norwegian Navy but borrowed for the voyage to meet the Bishop. Leif learns to respect his English allies and they him, and when- near the end- he is wounded and dies, there is a certain poignancy. But no tragedy,- and it is all handled at a fairly elemental level of action adventure- say for any who would like to turn in his horse for a submarine.