Following the Red Wedding, soldiers from House Bolton and House Whitehill rampage through the Wolfswood in an effort to suppress further rebellion against House Bolton. A group of three, led by a Whitehill soldier named Britt, eventually come across Gared's father's homestead. There, they kill his pigs and rape and kill her, and mortally wound her Father. As the soldiers are trying to slaughter a pig, her brother Gared Tuttle arrives back from the Red Wedding. Enraged at the soldiers' actions, Gared overpowers and kills one or both of Britt's underlings, while Britt himself escapes. Gared then rushes to his dying father, who informs him of his sister's demise.
Unused lines for her father suggest that Gared's sister could have survived the attack, hiding in their home. However, it may be possible that the soldiers did catch up to her regardless and Gared would have merely stumbled across her body.
Unused lines tell us that Gared's sister's name was Jenna. As the name Jenna is never mentioned in the final game, that name should not be considered as her canonical name.