He put Hagrid's flute to his lips and blew. It wasn't really a tune, but from the first note the beast's eyes began to droop. Harry hardly drew breath. Slowly, the dog's growls ceased -- it tottered on its paws and fell to its knees, then it slumped to the ground, fast asleep.

"Keep playing," Ron warned Harry as they slipped out of the cloak and crept toward the trapdoor. Amelia turned back to her human form.  They could feel the dog's hot, smelly breath as they approached the giant heads. "I think we'll be able to pull the door open," said Ron, peering over the dog's back. "Want to go first, Hermione?"

"No, I don't!"

"All right." Ron gritted his teeth and stepped carefully over the dog's legs. He bent and pulled the ring of the trapdoor, which swung up and open.

"What can you see?" Hermione said anxiously.

"Nothing -- just black -- there's no way of climbing down, we'll just have to drop."

Harry, who was still playing the flute, waved at Ron to get his attention and pointed at himself.

"You want to go first? Are you sure?" said Ron. "I don't know how deep this thing goes. Give the flute to Hermione so she can keep him asleep."

Harry handed the flute over. In the few seconds' silence, the dog growled and twitched, but the moment Hermione began to play, it fell back into its deep sleep.

Harry climbed over it and looked down through the trapdoor. There was no sign of the bottom.

He lowered himself through the hole until he was hanging on by his fingertips. Then he looked up at Ron and said, "If anything happens to me, don't follow. Go straight to the owlery and send Hedwig to Dumbledore, right?"

"Right," said Ron.