Williams appears as Arya Stark in the fifth episode of the second season of Game of Thrones, The Ghost of Harrenhal. Tom Wlaschiha plays the character of Jaqen H’ghar. An army of the Lannister noble family, the main rival to the Starks, is using the castle of Harrenhal as a base. Lord Tywin Lannister, played by Charles Dance, takes Arya into service as a cupbearer. He questions her about her northern accent but she manages to conceal her identity as a Stark. Arya encounters Jaqen H’ghar, who has been recruited as a Lannister soldier. As Arya had freed him from a cart during the battle in which her group of Night’s Watch recruits was captured by the Lannister men, he tells her that he is in her debt and will kill three people for her if she provides him their names. Arya gives the nickname of a soldier who had previously tortured captives, and later finds him dead.