Set in bustling Regency England and decaying Venice, 'A Man of Genius' portrays a psychological journey from safety into secrecy and obsession. After a troubled childhood, Ann achieves independence earning her living as an author of Gothic novels. Within a group of male writers, she meets and is enthralled by the supposed poetic genius, Robert James. They become uneasy lovers.

Ann and Robert travel from London through a Europe exhausted by the Napoleonic Wars. They arrive in a Venice of spies and intrigue, where their relationship becomes tortuous and Robert descends into near madness. Forced to flee with a stranger, Ann delves into her past to be jolted by a series of revelations about her lover, her parentage, the stranger, and herself.