Edward Landauer, a brilliant microbiologist in his forties, meets a beautiful young woman. She is the love of his life, and when the two marry in France, Edward is the happiest man in the world. At first, Ruth Walta appears to represent a victory over time, but even she cannot stop him growing older.

After the birth of their long-awaited son, the 'happiness, delicate like filigree' turns into something new, and Edward no longer recognises his great romance nor the woman who induced it.