In 1760, Guillaume le Gentil, real-life astronomer to King Louis XV, sets out for the oceans of India to document the transit of Venus. The weather is turbulent, the seas are rough and his quest may be more complicated than initially thought. 250 years later, estate agent Xavier Lemercier chances upon Guillaume's telescope in a property he's sold. As he looks out across the rooftops of Paris, he discovers an intriguing woman with a zebra in her apartment. Then the woman walks through the doors of his office, and his life changes forever.