"I think we should get back on topic," said Leo. "Does anyone have the time?"

Marisa glanced at her watch: eleven o'clock.

Leo hesitated for a moment. There was still quite a while left before lunchtime. "Okay," he said, "let's start by working on the Disarming Charm. If you've never learnt it before, line up here, if you've learnt it but haven't practiced much stand over here, and if you've mastered it stand over here."

The students divided up into three groups. The first-years were pretty evenly split between the first and second lines. Leo was joined in his line by all of the Slytherin second-years and two or three Ravenclaws.

"Okay," he said. "Um… Terry, could you supervise the first-years? I'll swap with you in a few minutes."

Terry nodded and walked off to instruct the first-years and some of the second-years who were learning and practicing the Disarming Charm.

Leo glanced around the remaining group: Marisa, Tracey, Theo, Daphne and Roger.

"Okay," he said, "let's play a game. Basically, we all have to try and Disarm each other, last one standing wins, no using any other spells."

Everyone nodded.

"Ready? Go!"

"Expelliarmus! Expelliarmus! Expelliarmus!"

For the first chaotic minute, Leo didn't actually aim any spells at anyone and instead focussed on dodging the jets of red light from all around. He noticed quite a few coming from a certain direction and guessed that Marisa was targeting him as she believed him the biggest threat. Which, of course, he was.

When the minute was up Tracey and Daphne were out and Marisa held two wands – he was pretty sure the second was Tracey's.

The remaining four stared at each other for a long moment and it was Marisa who made the first move. "Expelliarmus!" she said, one wand pointed at Leo and the other at Theo.

Leo had to admire her creativity and the strength of her magic in being able to wield two wands at once. He was relieved that it was Tracey's wand that was pointing at him, not Marisa's own, so the spell was weaker and easier to dodge.

Theo was not so lucky: his wand was ripped from his hand and Marisa caught it. She smirked.

"Expelliarmus," said Leo, knowing he had to take her down before she could focus solely on him.

Marisa dodged and, pointing all three wands at Roger, said: "Expelliarmus!"

Roger's wand was torn away from his grip and he was pushed backwards by the sheer force of the triple spell.

Marisa, grinning from ear to ear, caught Roger's wand.

Leo felt a strong sense of impending doom. "This is a health and safety risk!" he protested, pointing at Roger, who had collapsed to the ground under the sheer force of the spells. "We should make a rule saying – "

"You can't make rules in the middle of the game!" protested Marisa.

"I propose a vote," Leo suggested. "All in favour of a rule saying you should only be allowed to use one wand?"

Leo raised his hand. No-one else did.

"Um… can we have some reassurance that Marisa isn't going to make us vomit slugs if we vote for this?"

"I won't do that," she said, "but I'm not promising not to do anything…"

Roger cautiously raised his hand.

"All in favour of Leo getting his ass kicked?" asked Marisa with a grin.

Daphne, Theo and Marisa raised their hands.

"That's a clear majority, then…" she said smugly and pointed all four wands at Leo.

He knew that he wouldn't have any chance unless he acted before Marisa had the chance to, so he flicked his wand subtly at Marisa and whispered "Expelliarmus." Not waiting to see if the spell hit or not, he whirled around and began moving as quickly as he could in random directions. If he made himself a moving target, he might stand a chance.

As soon as he could, he glanced at Marisa to see what had happened: unfortunately, she was still clutching all four of the wands.

"Expelliarmus!" she said, and he was too slow to dodge: he was hit by all four spells.

He was forced backwards by the sheer power of the combined spells, his wand torn from his grasp by a powerful tug which he could do nothing at all to prevent. Then he hit something hard and heard a cry of "Ouch!"

He had been pushed back a good five metres and slammed directly into Theo's knees. The two Slytherins collapsed in a tangled heap.

"Do I win?" asked Marisa, walking towards them, now carrying five wands.

"Yes," said Leo grudgingly. "You win."