A historical drama set in Roman Egypt, concerning philosopher Hypatia of Alexandria and her relationship with her slave Davus, who is torn between his love for her and the possibility of gaining his freedom by joining the rising tide of Christianity.

Catherine is a woman in her late twenties who is strongly devoted to her father, Robert, a brilliant and well-known mathematician whose grip on reality is beginning to slip away. As Robert descends into madness, Catherine begins to wonder if she may have inherited her father's mental illness along with his mathematical genius.