Based in a small Russian town at the turn of the 20th Centaury, the play tells the story of the Prozorov sisters, Olga, Irina, and Masha (the 3 sisters of the title) and their brother Andrei, over the period of seven years. They all live together in the home they have shared from when their father (now deceased) was posted to the village. They spend their time dreaming of returning to the cosmopolitan life they lived in Moscow, seeking solace in the little society they can find in the form of the Soldiers that are posted in the area and the now ineffectual doctor Chebutykin.
Through the course of the play we see the transition of each Prozorov sibling. Andrei marries provincial girl Natalya, who starts taking over and running the family, while he squanders his early potential through gambling. Also, unbeknown to him Natalya commits adultery. Masha begins a romantic affair with Vershinin, an army officer with a sick and suicidal wife. A fire rages through the town and Dr Chebutykin is unable to help anyone. While Irina the most optimistic of the sisters, loses her chance of starting a new life when her fiancée is killed in a duel at the close of the play, just before the soldiers were to be reposted.