She wants to search for her daughters
From Create Your Own Story
"Look, Brienne, the only reason I'm sitting on that throne is so I can find my daughters. Are there any leads?"
Brienne looked Catelyn in the eyes, and the Queen knew the answer wasn't good. "Still nothing on Arya. Some suspect Littlefinger of stealing Sansa away. We don't know where he's gone either, though."
Catelyn sighed, clearing the despair out of her mind. "We need to locate Littlefinger regardless. Get Varys on the job. Give the spider a chance to prove his loyalty. As for Arya, send this message out to the farthest reaches of the Seven Kingdoms. 50,000 golden dragons and a lordship to whoever returns my daughter to me, alive, unhurt, and unspoiled." The thought of Arya being raped by some bandits made her hurt in a way only a mother can. Brienne nodded and left to carry out her Queen's orders.
"And Brienne," Catelyn called out.
Who does Catelyn want sent in?
