Proteus tells the Duke about Valentine’s plan to elope with his daughter Silvia. He insists that he would not normally betray his best friend in this way, but that the Duke’s generosity since Proteus’s arrival in Milan has made it impossible to for him to keep Valentine’s secret. He also suggests that he feared news of Silvia’s escape might kill the Duke, who plans to marry Silvia to Thurio. The Duke assures Proteus that he is aware of Silvia’s love for Valentine, whom he has been watching closely. To protect Silvia from Valentine, she has been locked in a high tower. Proteus explains that Valentine plans to free her from the tower with a ladder made of corded ropes. As Valentine approaches, Proteus leaves, encouraging the Duke to intercept him and confirm what Proteus has said without revealing his source.

Valentine attempts to leave when he sees the Duke, but the Duke dismisses his excuses. The Duke confides to Valentine that he is struggling to convince Silvia to marry Thurio, and that he has decided to disinherit her completely and marry a new wife, leaving his land and fortune to their new child.