Arya sits with Hot Pie in the kitchen, trying to convince him to give her a tart, when she hears the war horn signaling someone approaching the castle.
She runs outside and sees the Bloody Mummers returning with their plunder, prisoners of war, and a bear.
Ser Amory sends the captives to the great cell under the Widow's Tower.
As she heads across the bailey, Arya hears Gendry working the forge. She tries to convince him to hatch an escape plan with her, but he thinks it's ill-advised. Plus, he enjoys working the forge and doesn't care for whom he works it.
She goes to the godswood and finds her makeshift practice sword. As she practices, she is taken by the sudden urge to pray.
As if in answer, Jaqen H'ghar appears behind her, requesting a final name.
Arya requests he open the cell and free the captives, but Jaqen states the debt is for three men, and two have already been killed.
Arya names Jaqen H'ghar as her third death but says she'll name another if he helps her.
Jaqen tells her to come with him and obey.
Arya goes into the kitchen and has the chef prepare broth. Then Jaqen, Rorge, and Biter come to bring it to the guards guarding the great cell, Arya included.
They heave the hot broth onto the guards and kill them in the confusion.
Now free, the captives strip the guards of their weapons. Robett Glover wonders if they are Hoat's men—this suggests that Hoat smuggled them in the castle to usurp Ser Amory in the first place.
Arya agrees the debt is paid and unsays Jaqen's name.
Jaqen decides it is time for Jaqen H'ghar to die—and he changes his face before Arya, becoming a completely different person.
He gifts Arya an iron coin, telling her that if she ever wishes to find him again she need only give the coin to any man from Braavos and say, "Valar morghulis."
Come dawn, the fighting has ended and Ser Amory has lost Harrenhal.
Lord Roose Bolton enters the castle and both Hoat and Glover present it to him.
Arya is brought before Bolton, and he gives her the job of being his cupbearer. She provides another fake name, Nymeria, or Nan for short.
The Lannister banners are replaced with Stark and Bolton ones.
Later, Ser Amory is put in a pit with the bear and mauled to death. While pouring wine for Bolton, Arya thinks the bear looks especially like Yoren.