Em 1761, Catarina viaja para a Rússia e torna-se imperatriz ao casar com o Imperador da Rússia, Pedro. Com esperanças de desposar um grande amor, Catarina depressa percebe que Pedro é um fedelho egoísta que se opõe a tudo o que ela preza.

Catarina dá os primeiros passos para um golpe de estado. Aconselhando-se com Marial, ela tenta seduzir e recrutar o conde Orlo, um intelectual palaciano.

Catarina, Orlo e Marial continuam a planear o golpe de estado. Eles tentam recrutar Velementov, um general infeliz, para a causa deles, durante as festividades palacianas em homenagem do falecido pai de Pedro, Pedro, o Grande.

Catarina tenta gerir a sua reputação na corte e a sua relação com Leo, coisas que a distraem do seu golpe de estado. Entretanto, o influente Patriarca da igreja morre, e há que escolher um sucessor.

Enquanto a guerra na Suécia continua a grassar, Catarina e a tia Elizabete visitam o exército na frente russa. Ao ver os soldados, Catarina lembra-se do seu objetivo de governar a Rússia de forma diferente.

Pedro tem uma nova oportunidade de vida após quase morrer. Ele está recetivo às ideias progressistas de Catarina sobre arte e ciência, e quer focar-se num herdeiro. Orlo tenta descobrir quem envenenou Pedro e enfrenta alguns demónios seus.

Catarina sente-se otimista sobre uma coexistência pacífica com Pedro e a química crescente entre eles. Porém, quando deflagra um surto de varíola nos aposentos dos criados, Pedro volta aos seus velhos hábitos.

As capacidades políticas de Catarina são postas à prova quando ela tem a oportunidade de viajar para o estrangeiro com Pedro e Velementov para debater o fim da guerra com o rei sueco.

As tensões aumentam quando Catarina, Orlo, Velementov, Leo e Marial tentam obter o apoio dos condes regionais para o golpe de estado.

Catarina decide avançar com o golpe de estado no dia do seu aniversário. Pedro não se deixa ultrapassar tão facilmente e mantém Leo como refém para garantia.

Four months after she launched a coup against her husband, a pregnant Catherine is gaining the upper hand in her war against Peter. The fact that he is deeply in love with Catherine and their unborn child does little to dissuade her from taking his throne.

Catherine, Orlo and Velementov begin their rule of Russia and unexpected obstacles appear. Peter is on a journey of self-improvement under house arrest but convinces Catherine to let him attend her coronation and hand over his crown.

Catherine’s grief over the loss of Leo during the coup finally catches up with her. Peter’s part in Leo’s death, and the discovery that he just murdered a noble, causes Catherine to lock Peter in his apartments with only his mummified mother for company.

The Ottoman Ambassador pays Catherine a visit as tensions between the regions run high. But Peter fights to win his allegiance and prove to the court he is more fun than Catherine, in an attempt to destabilize her by throwing a baby shower.

A crocodile roams the court, and Archie sends everyone into uproar by suggesting it might be an omen against Catherine’s leadership.

Catherine is frustrated by the lack of meaningful change in her rule of Russia so far. Seeking to shake the court out of its complacency, she plays a joke on them involving a serf to prove a point, but it gets wildly out of hand with tragic consequences.

Catherine’s team is falling apart and she begins doubting her reign when her mother comes to visit. She works hard to hide the realities of the court from her mother and puts on a science fair for which Russia must come up with the best invention.

Elizabeth pronounces that Catherine’s baby will be born in 7 days and the court begins preparations involving rituals for Peter and Catherine. Conflict with the Ottomans heightens, and Catherine tries to run the country while on forced bed rest.

Catherine and Peter are co-parenting their newborn son, Paul, with the help of Elizabeth and trying to avoid their feelings for each other. When Paul goes missing, Peter and Catherine are driven together in their quest to find him.

Catherine makes a devastating discovery about Peter before traveling to the war front for a meeting with the Sultan. Peter considers his options now Catherine knows his secret and all parties come together for a final showdown at Marial’s wedding.

Catherine and Peter seek some marriage guidance after the chaotic events of the previous day left them in an awkward place in their relationship.

Catherine is visited by the UK and US Ambassadors both wanting her to intervene in the War of Independence. Maxim takes issue with the public displays of affection between Grigor and Marial.

Catherine involves the peasants, nobles and merchants in a conference designed to bring change to Russia. Peter’s hunt for revenge on an historic enemy threatens to destabilise Catherine’s attempt to outlaw murder.

Arkady and Tatyana help Peter and Catherine through a rough patch as they clash over their son Paul. Catherine fears Paul will grow up to be a ruthless and careless leader and Archie and Elizabeth are alarmed when Catherine refuses to ordain him.

Peter is once again tormented by his father, Peter the Great’s expectations and his failure to continue the legacy of his empire. Catherine must decide what to do about the unrest being stirred up in the regions, but Velementov is in no state to help her.

Catherine tries to persuade Peter to come home whilst Hugo re-doubles his attempts to regain his kingdom. Georgina continues to play her complicated court games.

Catherine wants to bring more fun to the court. With Georgina’s help she stages a festival of truth, jokes and stunningly clever ideas. Katya puts on a play that challenges Catherine’s reign, and Catherine samples Peter’s invention of salty desserts.

Catherine introduces divorce to the court with unforeseen consequences. Grigor befriends Maxim and goes stag hunting, and Elizabeth and Petrov go on a trip to the regions.

Under orders from Catherine, Grigor hides out in the forest with Paul. Catherine plays a dangerous game with herself to prove that her destiny lies in Russia, and grapples with the impact Peter’s decisions have on her rule.

Catherine meets court scientist Nikolai, who announces a comet is about to pass through Russia. She uses this phenomenon to her advantage and in the face of some huge challenges, unearths a new side of her leadership.