With a swagger, Percy walked up to the plate. He picked the bat up from where Jake had dropped it, and began to twirl it in his hands.

Percy had clearly played some softball before. The bat was like an extension of his arm. I watched as he swung it expertly, almost like a… a sword.

I frowned to myself.

Where did that thought come from?

The red-head had suddenly become a lot more animated. She was smiling at Percy, but it was probably the freakiest smile I had ever seen. It wasn't a smile that said, 'Hi! Nice to meet you', it was more the kind that said, 'Hi! I'm going to tear you apart and gnaw at your bones. With a side of salsa.' Looking at her smile, I realised that the girl's teeth were really sharp, like she'd filed them. In fact, they looked less like teeth and more like fangs.

'Peerseeus Jackson' the girl hissed. It was the first time I'd heard her speak, and it made me take a step backwards. When I say she hissed, I'm not exaggerating – her tongue flicked in and out as she spoke.

I looked around me, but no-one else seemed to have noticed anything out of the ordinary. They all looked like they always did during Phys Ed – bored.

Am I the only one seeing this? Seriously?

'Mormo' Percy replied, grinning. 'Long time, no see. You look good. Done something with your hair? Trying out some new eyeshadow? Let me tell you, it is working a treat.'

Mormo narrowed her eyes.

'Alwaysss with the jokesss. You made a mistake in coming here, Peerseeus. The one we came for isss but a small morsel – barely enough to whet my and my sister's appetites. But you, Son of Poseidon, you are a much juicier specimen. You will make a great feast for us.'

OK, I'll be honest with you – at this point, I was seriously freaking out. I didn't understand half of whatever this Mormo was talking about, but it sounded like she was some kind of serial killer. An extremely sexy, serial killer. I had no idea what to do.

No one around had noticed anything amiss – they seemed to think Percy was just stalling for time, and were starting to yell at him to get on with the game. It was like I was only one who could see what was happening.

'Percy' I asked, my voice breaking slightly with the fear. 'What the hell's going on?'

Percy meanwhile was leaning on his softball bat, nonchalantly checking his fingernails for specks of dirt.

'Chill, Castor. I've got this one under control' he said, like this was something that happened to him every other day. 'A girl wants to kill and eat me? Not again, that's twice this week. Can't a guy catch a break?'

Percy lifted the bat and pointed it at the girl he called Mormo.

'Look, sorry to spoil your fun Mormo, but I'm afraid Castor and I are off the menu. But I like you, I do, so I'm going to give you and your sisters a onetime opportunity to walk away now with those pretty little heads still on your shoulders. Only because I'm such a nice guy. Do we have a deal?'

The other two girls, the blonde and the brunette, joined Mormo and stood on either side of her, with matching evil smiles.

'Your bravado does you credit, little demigod' Mormo laughed. 'But we are not leaving this place until we are sated.'

Percy's smiled widened.

'I was hoping you'd say that.'

With astonishingly fast reflexes, Percy spun the bat until he held it in his hand like a javelin, then threw it. It hit Mormo in the face with a satisfying thump, and she howled in pain.

'Kill him!' she shrieked at her friends.

The girls snarled, and changed before my eyes. It was like an outer layer had been pulled off them; moments before, where I had been looking at beautiful girls, now stood the ugliest creatures I'd ever seen. They had big leathery wings, and claws, and their legs were those of animals – all hairy and muscled. Well, I guess it is true what they say – beauty is only skin deep.

People were screaming now – something about a giant flock of birds? I couldn't quite make it out amongst the noise. The class ran for the gym, despite the vocal protests of Coach Grigsby.

While everyone else made a break for it, two of the monsters came at Percy, who was rummaging in his pockets for something. Gum maybe? It's important to have good breath when you're just about to be ripped to shreds by crazy bird-women, I guess.

'Percy!' I shouted. 'What are you doing? Run!'

'Dude, I told you, relax' Percy called back. 'I promise, everything is under-'

One of the bird-ladies hit Percy, sending him flying backwards. He skidded across the grass, finally coming to a stop about fifty yards away.

'Percy!' I shouted.

I saw him raise a hand.

'It's cool' he replied, somewhat more faintly. 'Just a small hiccup in the plan.'

One of the bird ladies was descending on Percy from the air, her giant wings beating, claws outstretched. Just when it seemed like she had him in her clutches, there was a flash of metal and she exploded into dust, leaving nothing but a squawk of surprise behind.

Percy got to his feet and gave me a thumbs up. In his hand he held a sword – a real, full length sword. Where the heck had he been keeping that this whole time, stuffed down his shorts?

'It's all good' he told me. 'One down, two to go. Count 'em for me, Castor.'

The other bird-lady had backed up a little at seeing her friend disintegrate.

'You'll pay for that, half-blood' she spat.

Percy raised his free hand and made a beckoning motion, universal sign language for 'Bring it on.'

The bird-lady sprung, swiping at Percy's head with her talons. Percy ducked, rolled, then was back up again in time to parry a second attack. He feinted right with his sword, and when the bird-lady swept her claws up to defend herself, he quickly switched his attack to the left, driving the point into her foot.

The bird-lady cried something out in a language that half sounded familiar, but I couldn't quite place. Whatever she said, I bet it wasn't a compliment.

Percy kicked her in the chest, sending her sprawling. The bird lady spread her wings, frantically looking for a way to escape, but before she could lift off Percy bought his sword down and plunged it into her chest, and she disintegrated.

Percy let off a whoop, before blowing kisses to an imaginary crowd.

'He shoots, he scores' he called, waving his sword in the air. 'Rookie sensation Percy Jackson wows the fans. That's why they're already calling him the greatest demi-god of all time.'

This guy is seriously nuts.

Mormo was all on her own now, and was looking a lot less confident. Her tongue flickered as she licked her lips apprehensively. Percy flicked his sword up in her direction.

'Your turn Mormo' he said. 'Come on now, don't be shy.'

Mormo hissed, and unfurled her leathery wings.

'Ifff I can't have demi-god' she screeched, beating her wings and rising into the air, 'then mortal will have to do.'

Percy's smile dropped.

'Now you're not even playing fair' he complained. He ran at Mormo, and leapt, just missing her underside with his sword as she flew out of reach.

Mormo cackled, then angled towards the gym were I could see students milling about frantically. The fire alarm was blaring, which wasn't really helping to calm things down.

Percy stabbed his sword into the dirt and swore loudly.

'This is just great' he groaned. 'Chiron is not going to be happy. Typical monster, chickening out like that – right Castor?'

At this point, I was in a state of shock. Like when a little kid falls flat on their face and they just sit there for a while wondering what the heck just happened and waiting for the pain to kick in.

'Those girls had wings' I said matter-of-factly, as if it was the most normal thing in the world. 'They flew around. Then you killed two of them with a sword. An actual sword. Now one of them is going to eat everyone in the school. Have I missed anything?'

'Yeah, how awesome my moves were' Percy replied. 'Two outta three ain't bad. And the way nailed that first one when she thought she had me? That's gotta be in my top ten moves ever.'

'OK' I said, speaking slowly. All of this stuff was starting to give me a headache. 'Well, it was great to meet you Percy. Thanks for the show. I'm going to leave now.'

I turned, but Percy grabbed my arm.

'Dude, you can't leave' he said, his joking features suddenly serious. 'You won't be safe now. Ever. There's only one place that's safe for people like you – like us – and I'll take you to it.'

I laughed. 'If you think I'm going anywhere with you, you're even crazier than I thought.'

Percy shrugged.

'What was it you said to me before? It's your funeral. But the Mormolyceia were just the start. There'll be worse coming, a lot worse, and you don't want to be sticking round when they turn up.'

Percy turned towards the gym.

'Anyway, before we go anywhere, we've got an insanely hungry monster heading towards the school. And I don't think she's in the mood for burritos. Let's go.'

'Woah' I said. 'I can't stop that thing.'

Percy tutted.

'Course you can. You're a demi-god.'

'A what?'

Percy paused.

'Doesn't matter, I don't have the time to explain right now. Anyway, I'll do most of the work this time. You can just be my cheer squad.'

'Great' I replied. 'Sounds like fun.'

'Dude, I can never tell if you're being sarcastic or not. I just hope you're ready to show Mormo that the only thing on today's menu is celestial bronze, served Percy style.'