FF, Page 55.

I was walking down the side of a crater of a dead volcano. A mist hung in the air. There was a faint ringing sound. At the bottom of the crater was a lake. I walked on the black, shingle shore of the lake. Small bubbles were rising through the water. This was the source of the ringing sound. As I walked, I spied a small envelope on the black shingle. It had my name on it. I stooped to pick it up but when I straightened myself up again I found I was no longer on the shore of the strange lake at the bottom of a volcanic crater, but on the edge of a reservoir that for some reason I knew to be in Warrington. I still had the envelope. I opened it. There was a plain white card inside on which were written these words -- "You already know."