We are introduced to the correspondence between Christina and Descartes, which took place through the mediation of the French ambassador in Sweden, Pierre Chanut, with whom Descartes stayed on his arrival. Christina went so far as to offer Descartes transport to Sweden on a ship of the Swedish navy (official vehicles being used for seduction reminds the author of the case of a Swedish admiral who fell in love and learned to practise love with a mulatta in the West Indies). The sailors in the ship transporting Descartes to Sweden discover the wooden doll of a girl supposed to represent Francine, Descartes’ daughter by a domestic servant, Hélène Jans, who had died nine years earlier at the age of five.

The first part of the narrative is interspersed with letters written by Christina and Descartes, tracing their nascent and mutual admiration for each other until Descartes’ death, and with excerpts from a book for women written by Hélène Jans, which describes the properties and uses of numerous herbs such as yarrow, lady’s mantle, motherwort and others. At the end of the first part, Christina abdicates in favour of her German cousin Charles Gustavus and leaves Sweden in possession of Hélène Jans’ book of herbs for women.

In the second part, we are introduced to Hélène Jans in her home in Amsterdam, where she is reading a book on female anatomy (the narrative includes two excerpts from this book, which regards menstruation as divine punishment) and where she receives a visit from a friend, Camile, who requests a love-potion. Hélène attends the young daughter of Zacharias, who is about to give birth. She is known to prescribe herbs that will prevent conception or bring about a miscarriage, so the daughter is surprised that with her knowledge Hélène was unable to save her own child, Francine, who died of scarlet fever. She asks Hélène to tell her story. Hélène recounts how her father was a pharmacist and believed in an education for all his children, boys and girls, how she became interested in the medicinal properties of the herbs in his pharmacy, how she went to work as a washerwoman in the house of a famous bookseller in Amsterdam. In 1629 Descartes came to stay with the bookseller, and Hélène fell in love with his sensitive mannerisms. Every Thursday evening, Descartes would instruct the members of the household, servants included. He also talked about his life, how his mother had died giving birth to another child, but he’d been told it was giving birth to him, and how he had joined the army as an act of rebellion against his father. Amsterdam at that time was a vibrant city, owing to all the merchandise arriving from the Dutch colonies. Descartes talked about the mind and the stars while Hélène defended traditional knowledge, plants and the body’s sensations. They met one Sunday in the botanical garden and made love. Descartes received a letter, which proposed the idea of a universal language. Descartes rejected this idea, but Hélène was taken with the idea as a way of bequeathing her medical knowledge and wrote a treatise, Lingua nova e universalis, arguing that a common language was possible based on the rational ordering of philosophical thought. Descartes, in a letter, then embraced the idea.

After a relationship lasting five years, Hélène arranged to meet Descartes in Amsterdam’s botanical garden with a love-potion. Nine months later, in July 1635, their daughter, Francine, was born. At the risk of being branded a witch, Hélène devoted herself to acquiring greater medical knowledge, but in the spring of 1640 she learned that Descartes planned to separate her from their child, whom he wished to educate as a lady. Hélène took the decision to run away with the child and seek refuge in Amsterdam’s Jewish district, but before she could do so, Francine fell ill and died. This is the end of Hélène’s story and she urges the daughter of Zacharias to be quiet because she is about to give birth.

The second part of the narrative is interspersed with short poems and notes written by a university student, Einés Andrade, as well as letters and extracts from Hélène and Descartes’ works.