At the age of thirty-five, Fanny van de Grift Osbourne leaves her philandering husband in San Francisco and sets sail for Belgium to study art, with her three children and a nanny in tow. Not long after her arrival, however, tragedy strikes, and Fanny and her brood repair to a quiet artists' colony in France where she can recuperate. There she meets Robert Louis Stevenson, ten years her junior, who is instantly smitten with the earthy, independent and opinionated belle Americaine.

A woman ahead of her time, Fanny does not immediately take to the young lawyer who longs to devote his life to literature, and who would eventually write such classics as Treasure Island and The Strange Case of Dr. Jekyll and Mr. Hyde. In time, though, she succumbs to Stevenson's charms. The two begin a fierce love affair, marked by intense joy and harrowing darkness, which spans decades as they travel the world for the sake of his health. Eventually they settled in Samoa, where Robert Louis Stevenson is buried underneath the epitaph:

Under the wide and starry sky,
Dig the grave and let me lie.
Glad did I live and gladly die,
And I laid me down with a will.

This be the verse you grave for me:
Here he lies where he longed to be;
Home is the sailor, home from sea,
And the hunter home from the hill.

(Requiem, Robert Louis Stevenson)