The scene takes place in the royal palace in Poland. Dimitri has gone to Poland to persuade the Polish army to support him in his fight against Boris. The Poles are glad to do this because they often fought Russia when they thought they could take a bit of their land. They want the Polish Princess Marina to marry Dimitri (they think, of course, that he really is the Tsar’s son Dimitri, they don't know that he is really a young monk called Grigory). Princess Marina sings of her love for Dimitri. She has not met him yet, but she would like to be Tsarina (the wife of the Tsar) because that would bring her power. Rangoni tells Dimitri that the Princess is in love with him. A meeting is arranged in the garden. Princess Marina is horrible to him. She persuades him to act quickly to get an army together to march to Moscow and get the throne. They embrace. Rangoni is pleased, because it will be a triumph for his church.