The year is 1744, and a young woman  is torn from her homeland to marry the heir to the Russian throne. But his mother Elizabeth rules the Empire with an iron hand, while her son proves neither fit for the throne nor the marriage bed.

At risk from enemies who influence her husband, and treated as an outsider by the Empress Elizabeth, Catherine takes a lover and bears his child. Now, with the help of her best friend Sir Charles, she must take the throne by force if she, her illegitimate son and the Russian empire are to survive.