Theon has captured Winterfell with only 30 men, which is a bit of a precarious situation. So naturally he spends the night shagging while his 12 year old ward sleeps at the foot of his bed, as you do. So he misses the escape of the Stark boys, and Jojen and his sister, aided by Osha and Hodor.
Osha, I take it all back. All is forgiven, I was wrong, the Starks are clearly better judges of character than me.
Theon knows that without the Starks as captives it will be easy for the northern lords to re-take Winterfell. But he's mainly worried about looking like an idiot in front of his sister. Again.
He plays good cop bad cop with the small-folk and wonders why they hate him. He's basically Joffrey but with less self-confidence. Anyway, he spends all day running around following trails to nowhere and then Reek shows him a wolf brooch in a bag and suddenly he knows just where to look. But we'll have to wait for another chapter to find out what that's all about.