France, the mid-18th century. Jeanne is a peasant orphan, in love with nature and an expert in herbs and plants—yet she realizes that for a girl of her background the path to science is closed, and all that lies ahead is backbreaking work on a farm. But luck smiles on her: a talented assistant is noticed by a Dijon apothecary, who takes her in, while at the same time teaching her the basics of botany.
In his home, Jeanne meets the famed physician and naturalist Philibert Commerson—a young widower who needs a nanny for his newborn son. Showing quick wit and keen observation, Jeanne becomes not only a caring household helper, but also the scientist’s secretary and assistant, and then—his beloved. Their feelings cannot be indulged openly: the morals of the era do not forgive such connections. To avoid gossip, they move to Paris, and soon Commerson receives an invitation to the first French circumnavigation voyage led by Antoine de Bougainville. Does this mean they will have to part? After all, women are forbidden to board the ships of the Royal Navy…