The Hogwarts Students still stood outside, some of them were shivering now, waiting for the Durmstrang party to arrive. Most people were gazing hopefully up at the sky. But then a loud and oddly eerie noise was drifting towards them from out of the darkness; a muffled rumbling and sucking sound, as though an immense vacuum cleaner was moving along a river-bed. "The lake!" Lee Jordan yelled, pointing down at it. "Look at the lake!" he blurted out. 