SuperPotterLock- The Chamber of Secrets

The Polyjuice Potion

'Nice of you to turn up,' John huffed as Sherlock finally ambled into the hospital wing.

John and Justin had both been carried up to the hospital wing on stretchers by Professor Flitwick and the Astronomy teacher, Professor Sinistra. The lessons for the rest of that day had been cancelled and Professor McGonagall had begun marching around the corridors in an attempt to reign in the chaos caused by the double attack.

'Where have you been? I was looking for you,' John said.

Castiel had been put in charge of looking after John while Madam Pomfrey found a place for Justin and Nearly-Headless Nick. This wasn't easy as it was impossible to lay Nick on a bed. In the end, she settled for wafting him into a corner and conjured high curtains around him.

'I was- I was-'

'You were talking to Professor Lockhart, right?' John prompted.

Castiel clinked around, peering at different potions, trying to work out which ones would work on John, having already given him all the usual ones.

'-Yes, I was talking to Professor Lockhart,' Sherlock said uncertainly.

'Why?'

Castiel pressed a cold flannel to John's forehead and gave him a phial of purple potion. He accepted it and swallowed a mouthful. It tasted like ice and John shuddered. Castiel watched him closely for about a minute, then frowned. Evidently it had not done what he was expecting it to do.

'I can't give you any more potions,' he said. 'They might start to react badly with each other.'

'Why isn't it working?' Sherlock asked.

'I- I have to talk to Madam Pomfrey,' he stuttered, scuttling away.

John fell back against his pillows, feeling very tired now.

'You have to go home,' Sherlock said, looking at John. 'That could have been you.'

'I'm going home for Christmas. I'm fine.'

'It was very close, John. I want you to stay there.'

'You're not serious,' John laughed. Sherlock said nothing. 'No. Absolutely not.'

'You're not safe here.'

'So? Neither's anyone else. What're you going to do, send all the Muggle-borns home?'

Sherlock opened his mouth, but he was interrupted by Ron and Hermione hurrying up to them, closely followed by Molly Hooper. Castiel was suddenly there too, taking advantage of the distraction to garb Sherlock's arm and pull him away.

'What? What's wrong?' Sherlock asked.

'The only reason those potions wouldn't work is if it isn't a normal flu,' Castiel said.

'What do you mean?'

'We can't cure it because it's magical, and we don't know the cause.'

Sherlock stiffened.

'So he's been poisoned?'

Castiel fidgeted.

'Well...no. I don't think so. That last potion I gave him was meant to reveal any poisons in his system. It would have made him sneeze if there had been any.'

Sherlock stared at him, confused. He could hear the quiet murmur of voices behind him.

'So, what then?'