Most good stories start with a fundamental list of ingredients: the initial situation, conflict, complication, climax, suspense, denouement, and conclusion. Great writers sometimes shake up the recipe and add some spice.
Initial Situation
The family is gathered at Sorin's estate for the summer. Konstantin's premiering his play; it stars his love interest, Nina. At this point, it's all about possibility. Maybe Arkadina will love the play, maybe Nina and Konstantin will get engaged, who knows? We're waiting, along with the characters, to see what happens next.
Conflict
The play is a total flop and Nina meets the dashing Trigorin. Things are going downhill fast for Konstantin, and this sets off a string of events that begin to shape the story. We now know this isn't just a fun romp about Russian aristocrats putting on a play. Nina falls out of love with Konstantin and starts seriously eyeing Trigorin; Konstantin gives a hint of his extreme nature by presenting Nina with a dead seagull.
Complication
The attraction between Nina and Trigorin continues to develop, causing major problems for both Konstantin and Arkadina. Konstantin tries to kill himself.We'd call a suicide attempt a complication, wouldn't you? Things get pretty dark pretty fast. Nina and Trigorin want to take their relationship to the next level. Arkadina shows her ugly side, begging Trigorin to stay with her. And Konstantin and his mother continue to fight over her relationship with "that man."
Climax
Two years later, Nina comes in from the cold to see Konstantin, who has never let go of his love for her. He wants to understand her, and wants her to stay with him. He's hoping to regain the innocent love of their youth. But she's still hopelessly smitten with Trigorin—even though he cheated and left her and their baby.
Suspense
So this is the final blow for Konstantin. Cold, wet, homeless, childless, and poor, Nina still doesn't need him. How will he take it? Always concerned for his mother, he confesses the strange worry that she'll see Nina leaving and get upset. He tears up his manuscripts and leaves the room.
Denouement
Konstantin shoots himself—this time successfully. The family hears the gunshot. Immediately Dorn makes an excuse to protect Arkadina, and goes into the next room to investigate. Just a few lines remain until the end of the play.
Conclusion
The family is left with the reality of Konstantin's death. How will Arkadina react to her son's suicide? Chekhov doesn't show us. He leaves it hanging just before she finds out.