Harry had a lot of trouble trying to alert his companions to this fact. Everybody was shouting at the same time: Ron and Hermione were talking loudly at Hagrid; Sirius and Snape's voices were rising steadily as they argued over something, and Harry could see Lupin making placatory gestures, apparently to no avail.
"Er," he said. He was ignored.
"I think we ought to go now…" he tried again – and again no one paid the blindest bit of notice to him.
"Voldemort," he shrieked at last, hoping that he would finally get someone's attention. He was right. The room went silent, and everyone turned to stare at him.
"We know," said Lupin, eventually. "He's been behind – or in front of us – the whole time we were looking for you. We have to get out of here quickly, if we can."
Sirius seemed to notice Harry for the first time since he'd been able to talk. Striding forwards, Harry's godfather grabbed him by his arms, gave him a swift hug and then, to Harry's confusion, an abrupt shake.
"What are you doing?" shouted Sirius. "You could have got yourselves killed! What were you thinking of, coming down here – tonight of all times?"
Harry gaped at him. "But – " he said, well aware that Sirius was angry because he was worried, but at the same time too indignant to get the words out properly. Ron stepped in to rescue him.
"Dumbledore told us to!" he exclaimed, also evidently trying to understand the source of Sirius's fury. "He sent us down here! He said You-Know-Who was after us, and it was the only way, and that he'd come and join us as soon as he could!"
He, Harry and Hermione waited for Sirius to shout again, but to their surprise he gaped back at Ron.
"What?" he demanded.
"Dumbledore – told us to come here," repeated Ron cautiously. Sirius seemed to realise that his mouth was hanging open, and shut it with a snap.
"No he didn't," he said flatly.
"Yes he – " began Ron.
"Dumbledore couldn't have said anything of the sort," explained Sirius, interrupting him and suddenly looking extremely tired. "Because he's been with us, all day – a hundred miles away, gathering stray members of the Order of the Phoenix together. We didn't return until an hour ago. I'm not saying I don't believe you," he said, holding up a hand as three mouths were opened to argue with him, "I'm just saying: whoever it was you heard – it wasn't Dumbledore."