This story is set in Germany at the start of the First World War and follows Klaus, a quiet astronomer of Jewish background, who spends his time with a telescope in an observatory on the edge of town. There he meets an independent young woman from a well-to-do background whose desire for a career of her own leads her to work on the laboratory's microscope.

Their different backgrounds clash even as the world is changing around them. Ulla is forced to keep her work secret from her socially ambitious mother to whom status and the old ways are prized above all. Her father encourages Ulla to help him in his quest to find a cure for a deadly disease. However, he has a secret of his own which also threatens the stability of their family.

As their relationship grows and Ulla and Klaus share their scientific discoveries, unforeseen events force them to make choices which will have far-reaching consequences for both them and their families.