It is after sunset and a make-shift, homemade stage stands in the outdoor setting of Sorin's provincial, Russian estate and farm. A lake serves as natural scenery behind the stage. Medvedenko, a poor schoolteacher, believes he would be a happier man and a more attractive suitor to Masha if he had more money. Masha, the daughter of the estate manager, Shamrayev, fixates on her love for Treplev and does not agree. Snorting snuff, Masha openly acknowledges that she knows Medvedenko loves her but explains that she cannot love him back.
Treplev is nervous and busy as he gets things ready for the first performance of his play. Treplev tells Sorin that Arkadina is jealous of his play and hates it before she has seen it. Treplev picks a flower and pulls off its feathers saying, "She loves me, she loves me not," etc. He concludes that Arkadina does not love him. He longs to be accepted by her peers, the writers, actors and other artists who comprise the Russian intelligentsia and artistic elite based on his own work, not because he is the son of famous actors.
Nina arrives. She tells Treplev that her parents are afraid she will want to become an actress if she spends time with the bohemians at Sorin's estate. She says that it is the lake that attracts her to the estate, "as if I were a seagull." Nina and Treplev kiss. Treplev tells her he loves her, but Nina does not return his affectionate talk. Workers and guests interrupt their intimate moment.
We learn that Paulina loves Dorn and that they are involved in a romantic relationship but he is mostly apathetic about her affection. Arkadina shows off to the group by reciting lines of Gertrude in Shakespeare's play, Hamlet. Treplev responds by reciting Hamlet's lines back to her. His lines compare Arkadina's relationship with Trigorin to Gertrude's tainted relationship with Claudius. Treplev's play begins and recites a long monologue about a universal soul and man's place on earth into infinity. It is abstract and symbolic. Arkadina rudely interrupts the performance several times by talking out loud to her friends in the audience. When a special effect of red lights in the form of two eyes and the smell of sulpher rises in a cloud from the stage, Arkadina makes such a fuss that Treplev ends the play and closes the curtain. He runs off.
Nina meets Trigorin for the first time. Arkadina laughs at Nina's awe of Trigorin's role as a creator. Treplev desperately desires Nina but learns that she has already left. He runs off. Masha takes a pinch of snuff. Dorn criticizes her. She admits to him that she is in love with Treplev. Dorn sighs over the abundance of unrequited love in his presence.
Shamrayev and Arkadina argue about the use of the horses. Arkadina wants to use them later in the day to go into town. Shamrayev has them out in the field. He stubbornly will not allow her to use them later. She threatens to leave the estate and return to the country. Nina gives Dorn a bouquet of fresh picked flowers. Paulina takes the flowers from him and destroys them.
Nina is the only one left onstage. She comments that she is surprised that Arkadina and Trigorin act like normal people even though they are famous. Treplev enters with a rifle and a dead seagull in his hands. He puts the seagull at Nina's feet. He tells her that he shot the bird in her honor and that one day he will be like the seagull. Nina and Treplev fight about their relationship. She accuses him of talking in symbols. He laments her change from warm to cold. Treplev expresses his conclusion that Nina stopped loving him because his play was a failure. He compares Nina's faded love for him to the lake disappearing into the ground.
Treplev exits bitterly when he sees Nina's fondness for Trigorin. Trigorin brings up the news that he and Arkadina are leaving the estate to go back to town. Trigorin explains the obsessive-compulsive behavior that forces him to document everything he observes in his memory and on paper for future use in a story. Trigorin sees the seagull that Treplev shot. He writes down a note about Nina, saying that she has inspired him to start a new story about a girl who is ruined by a man just like the seagull that Treplev destroyed, because he has nothing better to do. Arkadina interrupts Trigorin and Nina when she calls to Trigorin announcing that she has been convinced to stay on the estate.
Contrary to the conclusion of Act Two when Arkadina decides to stay, Act Three begins with Trigorin eating lunch in Sorin's dining room, surrounded by packed luggage. Masha keeps Trigorin company, confessing her plan to marry Medvedenko. Nina gives Trigorin a parting gift of a medallion with his initials inscribed on one side and the title of his book, "Days and Nights" on the other. She asks him to give her two minutes more before he leaves. Trigorin discovers that inscribed on the medallion is a page and line number from his book. As he goes off stage to find the book in order to read the quote to which Nina's gift refers, Arkadina argues with her brother, Sorin about his joining them into town. Sorin falls ill for a few moments and Arkadina becomes frightened. She screams for help.
Treplev asks Arkadina to change the bandage on his head. They share some tender moments of lightheartedness but their conversation disintegrates into name- calling, insults, and competitiveness. Treplev ends up crying because he mourns the loss of Nina's affection. Arkadina tries to cheer him up and tells him that Nina will soon come back to him because Arkadina is taking Trigorin away from the estate. Trigorin enters, mumbling the line from Nina's inscription, "If you ever need my life, come take it." He muses over the line and it means something to him. He asks Arkadina if they can stay.
Arkadina challenges Trigorin about his interest in Nina, bringing to the forefront, the tension that has existed only in silence. Trigorin portrays himself as a man who missed out on the splendors and excitement of youthful love because he spent his youth writing to make a name for himself. Fearing the loss of the man she loves, Arkadina pleads, kisses, flatters, and begs on her hands and knees for Trigorin to leave with her. Her persuasive talk convinces Trigorin to leave, but, when Nina and he catch a few private moments before he leaves, Nina tells Trigorin her plan to move to Moscow at once and to try her luck at an acting career. Trigorin tells Nina to stay at the Slavyansky Bazaar Hotel. He asks her to let him know as soon as she gets there. Before he rushes off to get in the carriage, he steals a long passionate kiss from Nina, sealing their promise to meet again.
It is two years later than Act Three. On a stormy night, Medvedenko and Masha discuss Sorin's request to see Treplev as his health fades. Medvedenko pleads with Masha to go home with him to their baby. Masha refuses. Masha makes a bed for Sorin on the divan. Paulina comments that no one thought Kostya would become a genuine writer, but now he is making money writing and looks handsome. Masha tells her mother that Medvedenko has been offered a teaching job in another district, and they are to move away in a month.
Dorn asks Treplev about Nina's life now. Treplev tells Dorn that Nina had an affair with Trigorin and became pregnant. But, the baby died and Trigorin left her for Arkadina whom he was with while he impregnated Nina, cheating on them both.
Treplev recounts how Nina played starring roles in summer theater plays outside of Moscow that moved to the provinces but that she played her parts badly. He used to visit her on the road and see her perform, but Nina refused to see him. Treplev eventually gave up on following her around. Nina would send Treplev troubled letters and sign them, "The Seagull." Treplev compares Nina's signature to a character in a Pushkin play who signs his name, "The Raven." Treplev reveals the information that Nina is staying nearby in town at a hotel. Masha went to see her, but Nina refused to talk to her and Medvedenko swears that he saw her walking through a nearby field. Nina's parents have hired armed guards to keep her away from their house next door to Sorin's estate.
Trigorin brings him a copy of the latest magazine in which a story of his is published. Arkadina begins a game of lotto. She recalls her family's tradition of playing the game to pass the time. Treplev notices that Trigorin read his own story in the magazine but did not bother to read Treplev's.
Shamrayev tells Trigorin that he stuffed the seagull that Treplev shot for him. Trigorin does not remember asking Shamrayev to stuff and mount it. Arkadina calls everyone to dinner and asks Treplev to stop writing.
Treplev is left alone in his study. He looks over his writing and criticizes himself out loud for being cliché. He compares his writing to Trigorin's with envy and despair. He hears a knock on the window. It is Nina. Nina enters the house paranoid about Arkadina finding her there and asks him to lock the door. Treplev props a chair against the door. Nina and Treplev admit to each other that they have sought each other. Nina's speech becomes fractured and confusing. She cuts off her own thoughts. She says she is "the Seagull" and compares herself to a homeless wanderer in a Turgenev story. She cries. She says she feels better because she has not cried in two years. Nina acknowledges that Treplev is now a writer, and she became an actress but her life is difficult. She thinks nostalgically about their youth and their youthful love.
Treplev professes his love to Nina and recounts his torment when she left him, how nothing he has accomplished has been meaningful to him because she was not present to share in his successes. Nina tells Treplev about the depression she suffered when she realized she was a bad actor. Her story breaks down, and she repeats Trigorin's idea for a story about a girl who is destroyed like the seagull by a man who has nothing better to do. She concludes that what is important for an artist is not how successful you are but that you persevere. Nina becomes weaker. Treplev asks her to stay. Nina confesses to Treplev that she still profoundly loves Trigorin. She remembers the innocence and hope that she and Treplev felt the summer they put on their play. She recites lines from the play. Nina hugs Treplev and then runs out of the door.
Treplev proceeds to tear up his manuscripts and throws them under his desk. Arkadina and the rest of the household come back from dinner and start another game of lotto. Dorn pushes in the door that Treplev propped closed with a chair. Shamrayev presents Trigorin with the stuffed seagull. Again, Trigorin says he does not remember asking for it to be stuffed. A shot goes off in a loud bang, offstage. Arkadina becomes frightened. Dorn calms her down presenting the thought that the sound was probably only a popped cork in a bottle in his medicine bag. Dorn goes to check on the sound and comes back to the group. He takes a magazine and brings Trigorin aside, pretending he is interested in discussing an article on America. Dorn tells Trigorin that he needs to get Irina Arkadina out of the house quickly because Treplev has shot himself. Arkadina does not hear Dorn's sad news before the play's end.