Felton rides to Portsmouth, where the Duke of Buckingham is staying. He is let into the duke’s chambers because Felton is well-known at court for his proximity to Lord de Winter, a close friend of the duke’s. To test the duke against what Milady has said, Felton shows him Lord de Winter’s orders for Milady to be sent to a penal colony. When the duke eagerly signs the documents, calling Milady an infamous villain, Felton is driven to “madness.” He yells at the shocked duke and stabs him just as Lord de Winter arrives, eager to find his friend—when Lord de Winter realized that Milady and Felton were gone, he assumed that Felton was under her sway and was likely going to kill the duke.

A cannon sound in the distance implies that something else is also going wrong. As he dies, the duke dictates a note to Queen Anne, requesting it be sent to her alongside the love tokens she gave the duke and the knife that killed him.

Meanwhile, Felton sees Milady sail away early, leaving him behind. He understands that he’s been tricked into murdering the Duke of Buckingham.