Three Hearts and Three Lions

Three Hearts and Three Lions is a 1961 fantasy novel by American writer Poul Anderson, expanded from a 1953 novella by Anderson which appeared in Fantasy & Science Fiction magazine. == Plot == Holger Carlsen is an American-trained Danish engineer who joins the Danish resistance to the Nazis in World War II. At the shore near Elsinore, he is among the group of resistance fighters trying to cover the escape to Sweden of an important scientist (evidently the nuclear physicist Niels Bohr).

Source: Wikipedia — Three Hearts and Three Lions (CC BY-SA 4.0)