How It All Goes Down
In Act 1, The Nikolaev family is gathered at their awesome summer home. Big brother Sorin, sixty years old, lives at the estate. His famous sister, Arkadina, has arrived for vacation with her lover Trigorin. Arkadina's son Konstantin has been laboring at an original play that premieres that night and stars the beautiful neighbor girl Nina. What could go wrong, right?
Everything.
Other friends and neighbors will attend the performance: Shamrayev, the farm manager, his wife Paulina, and his daughter Masha; Masha's suitor Medvedenko; and the local doctor Dorn. It's exciting! But it's a disaster. Jealous, spiteful Arkadina undermines the performance and upsets her son Konstantin. He's distraught because he failed in front of Nina, whom he loves.
A couple of weeks later, in Act 2, Nina has fallen out of love with Konstantin. When he shoots a seagull and threatens to kill himself, she just moves farther away from him—and toward the writer Trigorin. The attraction is mutual, to the fury of Arkadina.
This isn't the only love triangle in the play, however: Medvedenko's in love with Masha; Masha's in love with Konstantin; and Paulina's in love with Dorn (don't forget—she's already married). Sorin's getting sicker and Shamrayev still enjoys torturing the aristocrats by denying them horses.
In Act 3, Arkadina and Trigorin are preparing to return to Moscow. Nina indirectly declares her love for Trigorin, who feels the same way. He'd like to stay. No way no how, says Arkadina, and pulls out all the actressy stops to get him back—for now. She's much more concerned about preserving her romantic relationship than the one with her son, who has shot himself in despair over Nina's rejection. Arkadina leaves the house with Trigorin, but not before he has promised to see Nina in Moscow. Masha plans to marry Medvedenko.
Act 4 begins two years later. Masha is unhappily married to Medvedenko, and they have a neglected baby. Konstantin lives at home with his uncle. He recounts the sad story of Nina, who hooked up with Trigorin, lost the baby, and was abandoned. And has become a mediocre actress.
Because Sorin is very ill—maybe dying—Arkadina and Trigorin drop in to visit. The glamorous couple offers mildly encouraging words to Konstantin, who has become a published writer. While the others socialize, Konstantin receives a visit from Nina. Nervous and ill, she's just stopped in before she has to be on her way again to an acting gig in a small town. Konstantin begs her to stay with him but Nina, still in love with Trigorin, rejects him. She leaves, and Konstantin goes into the next room. He shoots himself.