Don't highlight any of these spoilers unless you've read CoK.
Heh, not true. You're remembering wrong.
Quoting from the book
“M’lord prince.” Reek urged his horse near. “Might be them Starks never came this way. If I was them, I would have gone north and east, maybe. To the Umbers. Good Stark men, they are. But their lands are a long way. The boys will shelter someplace nearer. Might be I know where.”
Theon looked at him suspiciously. “Tell me.”
“You know that old mill, sitting lonely on the Acorn Water? We stopped there when I was being dragged to Winterfell a captive. The miller’s wife sold us hay for our horses while that old knight clucked over her brats. Might be the Starks are hiding there.”
Theon knew the mill. He had even tumbled the miller’s wife a time or two. There was nothing special about it, or her. “Why there? There are a dozen villages and holdfasts just as close.”
Amusement shone in those pale eyes. “Why? Now that’s past knowing. But they’re there, I have a feeling.”
Ahh I am totally misremembering..
I remember the stuff about the Mill, but I thought that was a bit earlier before Theon figured out the plan
That makes it even more clear though..