You have no desire to be involved in building the Great Wall of China, or, for that matter, to be taken to another planet by aliens. You walk back into the crevasse, hoping to find a tunnel that might lead to another time. You walk along the bottom of the crevasse and reach an opening on the other side of the ridge, where you half expect to see the rolling countryside, the stream and the space ship that were there before.

Instead, the crevasse leads to the ocean! Like a bad dream, where the scene suddenly changes into something entirely different, you find that the hills have become waves, which surround you so that the rock you are standing on is only a reef protruding a few yards above the wind-swept seas. And there seems to be no escape, because, for all you can tell, you are standing on the only land in the world.