That night we went back to the house. When we saw Helen Stoner's light Holmes and I got in quietly through the window. Then we waited silently in the middle bed-room in the dark. We waited for three hours and did not move. Suddenly we saw a light and heard a sound from Dr Roylott's room. But nothing happened and again we waited in the dark. Then there was another sound a very quiet sound .. . Immediately Holmes jumped up and hit the bell-rope hard. 'Can you see it Watson?' he shouted. But I saw nothing. There was a quiet whistle. We both looked up at the air-vent and suddenly we heard a terrible cry in the next room. Then the house was silent again. 'What does it mean?' I asked. My voice was shak-ing. 'It's finished' answered Holmes. 'Let's go and see.'