When an epidemic threatens to destroy the silk trade in France, the young merchant Herve Joncour leaves his doting wife and his comfortable home in the small town of Lavilledieu and travels across Siberia to the other end of the world, to Japan, to obtain eggs for a fresh breeding of silk worms. It is the 1860s; Japan is closed to foreigners and this has to be a clandestine operation.
During his undercover negotiations with the local baron, Joncour's attention is arrested by the man's concubine, a girl who does not have Oriental eyes. Although the young Frenchman and the girl are unable to exchange so much as a word, love blossoms between them, conveyed by a number of recondite messages in the course of four visits the Frenchman pays to Japan. How their secret affair develops and how it unfolds is told in a narration as beautiful, smooth and seamless as a piece of the finest silk.