People living at a seashore town are frightened by reports of an unknown creature called "the sea devil". Nobody knows what it is, but it's really the son of doctor Salvator. The doctor performed surgery on his son and now young Ichtiander can live under water. This gives him certain advantages, but also creates a lot of problems.
Young patriotic young man ends up in the on Chukotka right after the civil war, where he intends to spread ideas of justice and equality among the natives. As it happens, instead he learn the local capitalist ways, and he start profitable fur trading with US, Japanese and other merchants.
A group of Russian partisans hiding within a remote forest attempt to destroy a nearby German airfield, all the while assisting a downed French pilot who happens to fall madly in love with a local girl.
