"What are you doing?" Filch snarled suspiciously. "Nothing," said Harry truthfully.

"Nothing!" spat Filch, his jowls quivering unpleasantly. "A likely story! Sneaking around on your own -- why aren't you in Hogsmeade buying Stink Pellets and Belch Powder and Whizzing Worms like the rest of your nasty little friends?"

Harry shrugged.

"Well, get back to your common room where you belong!" snapped Filch, and he stood glaring until Harry had passed out of sight.

"Slime is set," Amelia grinned, turning viable by Harry's side and rubbing her hands together.

"We are going to get in a lot of trouble."

"Oh, lighten up. He can't prove anything." 

But Harry didn't go back to the common room; he climbed a staircase(Amelia crawling up beside him like a dog), thinking vaguely of visiting the Owlery to see Hedwig, and was walking along another corridor when a voice from inside one of the rooms said, "Harry? Amelia?"

Harry doubled back to see who had spoken and met Professor Lupin, looking around his office door. Amelia straighten up. 

"What are you doing?" said Lupin, though in a very different voice from Filch. "Where are Ron and Hermione?"

"Hogsmeade," said Harry, in a would-be casual voice.