Williams appears as Arya Stark in the sixth episode of the second season of Game of Thrones, The Old Gods and the New. Charles Dance plays Lord Tywin Lannister and Aidan Gillen plays Lord Petyr Baelish, the royal treasurer. At the Lannister army encampment at Harrenhal castle, Lord Tywin has taken Arya into service as a cupbearer. Arya is surprised by the visit of Lord Petyr, who she is familiar with from her time in King’s Landing, but she is able to keep her identity as a Stark secret from him and from Lord Tywin. While Lord Tywin is distracted, she notices that a letter on his table refers to her older brother Robb Stark, who is fighting a war with the Lannister armies. She steals the letter and runs outside, but a Lannister loyalist sees her carrying it and becomes suspicious. She is able to alert Jaqen H’ghar, an assassin who is in her debt, and he kills the man before he is able to inform Lord Tywin of what he saw.