Treplev and Medvedenko enter from off-stage at the sound of Arkadina's cry for help. Treplev calms down his mother, informing her that Sorin frequently has harmless dizzy spells. Just as Sorin suggested that Arkadina loan Treplev some money just moments ago, Treplev suggests that she lend Sorin some money so that he could live in town. Arkadina defends herself by saying she does not have any extra money. Treplev asks Arkadina to change the bandage on his head from his injury caused by his attempted suicide. They share some tender moments of lightheartedness, but their conversation disintegrates into name-calling, insults, and competitiveness. Their insults include their poor opinion of the other's artistry. Treplev ends up crying. Treplev cries in part because of the divide between him and his mother and his inability to win her over to respect his talents, but he only reveals to Arkadina that he is upset because he mourns the loss of Nina's affection. This too also bothers Treplev greatly, complicating his already depressed situation. 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. It means something powerful to him. As Masha requested, Trigorin asks Arkadina if they can stay after all.
Arkadina challenges Trigorin in regards to his romantic interest in Nina. She brings to the forefront all of the sexual tension that has existed only in silence between Trigorin and Nina and Trigorin and Arkadina. Trigorin selfishly attempts to convince Arkadina that if she were to allow him to become Nina's lover, the sacrifice would make her a great woman. Arkadina accuses Trigorin of being in a state of a drunken stupor with his illusion of a relationship with such a young, naive girl as Nina. Arkadina casts Nina as a girl who has none of the experience, intellectual heft, or challenges as an older woman like Arkadina. 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 her loss of the man she loves, Arkadina pleads, kisses, flatters, and begs on her hands and knees for Trigorin to stay with her instead of fleeing to Nina.
Arkadina's persuasive maneuvers convince Trigorin to leave with her and forget his feelings for Nina. Trigorin fulfills his promise to Nina to give her two minutes in private before he leaves. Nina tells Trigorin that she plans to move to Moscow to be near him, immediately, and to try her luck at an acting career. Trigorin tells Nina to stay at the Slavyansky Bazaar Hotel in Moscow. He asks Nina to send him word that she has arrived as soon as she gets to the hotel. Before he rushes off to get in the carriage with Arkadina, he steals a long passionate kiss from Nina, sealing their promise to meet again.
Something significant changes in Trigorin when he discovers the line to which Nina refers on the medallion she gives him as a parting gift. Trigorin experiences a sudden surge of meaning and excitement for his life upon forming a bond with Nina. As Trigorin explains to Arkadina, Nina promises the hope of youthful love and represents an innocent beauty that Trigorin never experienced as a youth because of his writing pursuits. Trigorin worked hard as a young man to forge his writing career. In his mind, for his career, he sacrificed the chance to have relationships such as the one he could have now with Nina. Nina seduces Trigorin with her flattery of his talents, awe of his position in life and personal challenge to his assumptions and opinions. Nina inspires him to have a second chance by reliving a romantic youth he sacrificed in order to become an established writer. When Trigorin succumbs to Nina's charm and advances, he suddenly transforms his role from passive spectator of the play's main events to proactive participant and shaper of lives. When Trigorin decides to take Nina up on the affair, inevitably Arkadina, Treplev, and Nina's lives will be affected by his decision.
Trigorin plays God with Arkadina, Treplev, and Nina's hearts, choosing for himself the fate of their love. He chooses to be with Nina not because he wants a mutual relationship with her but because he wants to experience something new for himself. Trigorin acts out of lust, selfishness, and a belief in the illusion of extending youth. Trigorin reveals more about his character in his scene with Nina as he expounds upon his life as a writer. He describes himself as a man unable to be permanently fulfilled or satisfied with a result. Trigorin explains to Nina his compulsive need to constantly observe the details around him of life, people, and of nature. Trigorin's powers of description and observation are great. Chekhov shows that Trigorin obviously has a knack for writing. It is ironic, however, that Trigorin observes more about the outside world than the emotional world of the lives around him. A counter-point to his lover, Arkadina, who observes not her own true self, nor the feelings of those around her, Trigorin observes much around him but also lacks an ability to gain personal insight or feel compassion for others. We get the feeling in his decision to have an affair with Nina that his reasoning for it does not extend beyond lust, personal triumph, and curiosity. Trigorin's relationship with Nina, we are promised, will be little more than another sensual account that Trigorin will mutate into fiction, publish, and then forget about when he moves on to his next story. Nina, however, places her whole faith into the new partnership. Arkadina loses a large part of her reason to take pride in her life when she loses Trigorin to Nina. Treplev loses Nina as a result of his mother's lover, another strike against Arkadina in his eyes. Though the relationship is bound to cause damage, Trigorin seems unaware that his decision will affect anyone but himself.