Mrs Blackett says that the doctor has gone … up the valley to Nook Farm, where somebody’s broken an ankle.
They go to stop the doctor, so that he can look at Nancy. They came to the place where the road forked. To the right, it turned sharp over a bridge, crossing the river, on its way to the head of the lake and round to the little town that the Swallows and Amazons never called by any other name than Rio. To the left, it turned up the valley between the fells. Nook Farm was up that road, and the Doctor would have to cross the bridge on his way home (WH8).