Growing weary of the festivities, Jack sallies forth for more adventures and meets an elderly man who directs him to an enchanted castle belonging to the giant Galigantus (Galligantua, in the Joseph Jacobs version). The giant holds captive many knights and ladies and a Duke's daughter who has been transformed into a white doe through the power of a sorcerer. Jack beheads the giant, the sorcerer flees, the Duke's daughter is restored to her true shape, and the captives are freed.
At the court of King Arthur, Jack marries the Duke's daughter and the two are given an estate where they live happily ever after.