He comes across a woman clad in green, who claims to be the daughter of the troll mountain king. Together they ride into the mountain hall, and the troll king gives Peer the opportunity to become a troll if Peer would marry his daughter. Peer agrees to a number of conditions, but declines in the end. He is then confronted with the fact that the green-clad woman is with child. Peer denies this; he claims not to have touched her, but the wise troll king replies that he begat the child in his head. Crucial for the plot and understanding of the play is the question asked by the troll king: "What is the difference between troll and man?"