The Boltons know they need Sansa (Sophie Turner) back in their clutches if they're ever going to successfully hold on to the North, and Ramsay's (Iwan Rheon) efforts to track her down will lead to an ambitious endeavor on Game of Thrones.

Ramsay was already warned by his father, Roose (Michael McElhatton) that if he couldn't find Sansa and produce a male heir in time, the child he is expecting with Walda--especially if it is a boy, will inherit everything Roose has, and Ramsay will be considered as good as the b**tard he initially was. Now, Ramsay will be more determined than ever to find her, especially when his search turns up nothing, and he will unveil to his father what he plans to do to find Sansa, since he's sure he knows exactly where she's headed.

"We know where she's going," he says in a preview clip for the Sunday, May 1 episode. "Castle Black isn't defended on it's other side. We could storm the castle."

Ramsay will be assured that Sansa and Theon (Alfie Allen) are headed to the Wall to meet up with, and get protection from, her brother, Jon Snow (Kit Harington), though he's unaware that such an attempt to meet up with him would be fruitless, since he is dead.

Meanwhile, Sansa and Theon were rescued from Ramsay's hounds and men when Brienne (Gwendoline Christie) and Podrick (Daniel Portman) happened to find them and slaughtered the Bolton men. Now, the group is traveling together, and Sansa is learning more about Brienne's vows to protect her and Arya (Maisie Williams), and she will be stunned to learn that her little sister is still alive, even though they don't know exactly where she is.

"You don't know which way she went?" Sansa asks in the clip.

"I spent three days looking for her. She disappeared," Brienne responds.

Game of Thrones airs Sundays at 9 p.m. on HBO.