The play opens in the richly furnished study at Werle's house. It is the evening of a dinner party celebrating the return of Werle's son, Gregers, from the Hoidal mines. Gregers has not come home for fifteen years. The dining room adjoins to the left; to the right, a baize door leads to Werle's office. Pettersen, a servant, and Jensen, a hired waiter, put the room in order. The sound of a toast is heard in the next room.

Pettersen declares that Werle is droning on about his lover Mrs. Sorby; the two men bawdily joke about their affair. Suddenly Old Ekdal, dressed in a threadbare overcoat and a dirty red-brown wig, appears from the right, begging to be let into the office. Warning him against appearing in front of the company, Pettersen lets him pass.

Pettersen explains to the waiter that Ekdal was once an army officer and partner to Werle at the Hoidal works. He apparently played some dirty trick on Werle and went to prison; now he works as one of Werle's copyists.

The dining room bursts open, and the jovial guests appear. Mrs. Sorby sends the servants to prepare coffee in the music room. Glancing dejectedly at Hialmar Ekdal, Werle remarks to Gregers in a low voice that it would seem no one noticed that there were thirteen at the table.

All except Hialmar and Gregers move to the music room. Hialmar, who has overheard the conversation between father and son, remarks that Gregers should not have invited him since he is outside his father's circle. Gregers insists that he had to catch up with his boyhood friend. When he compliments Hialmar's "outer man," the latter confesses an inner gloom in the wake of his father's scandal. Apparently Hialmar had feared that Gregers bore him ill will. Werle's father at least had given him this impression and instructed him to give up all contact with his son.

Hialmar tells of his life after his father's disgrace. To Gregers surprise, Werle urged him to leave the university, helped him begin his photography studio, and made it possible for him to marry. Coincidentally, his wife, Gina, worked in Werle's house during the last year of Mrs. Werle's illness. They met through Werle's interventions as well. Despite Werle's assurances that he had regularly written his son with news, Gregers has known nothing of these events.