Anger rose up in me and I stormed over the wire fence.

‘Get away from that tree,’ I shouted at Liam, who was still crouching beside it.

Surprised, he wobbled on his heels and toppled over on the muddy ground.

‘Ow,’ he yelled and pulled out a thistle the size of his arm from under his bum.

‘Serves you right,’ said Kai behind me.

‘Whatever you’re doing, stop it!’ Kat shouted. ‘You’re killing the tree!’

‘Rubbish,’ Liam said, scrabbling to his feet and looking round for his dragon. ‘I’m making things grow huge. Well, that thing is anyway.’

‘That THING?’ shrieked Kat.

Liam really had done it now.

‘You mean the awesome dragon you’ve been lucky enough to be looking after? Although looking after is hardly what I’d call what you’ve been doing. Besides,’ she added, ‘that dragon might be super-sizing the fruit and veg, but the plants are dying afterwards. It’s draining all the goodness and life out of the soil and the plant. What’s the use of one gigantic fruit if the tree dies?’

Liam looked round at the garden and shrugged like he didn’t give one hoot about a bunch of stupid plants.

Kat launched herself at him, and for once I was the one holding her back.

‘Listen, Liam …’ I said. I took a deep breath and thought about Grandad.

Maybe I could employ a bit of his philosophy about seeing the good in everyone and appeal to Liam’s better side. I stepped in closer, keeping my voice as calm as possible. ‘The thing is, Liam, your dragon is causing chaos. And the more chaos it causes, the more likely it is someone’s going to notice. We have to protect the dragons. And that means keeping them secret.’

I waited, willing him to understand and to do the right thing. We all waited. Even the dragons seemed to stop flitting about above our heads.

But then he just narrowed his eyes and glared at us, taking his time to eye up each one of the superhero squad as we stood there together.

‘You wait till I get a super-size dragon. Then you’ll see some proper chaos.’ And he snorted out a maniacal laugh, reached forward and grabbed at the fruit, which had now swollen to the size of a beach ball.

Wrapping his arms around it, he heaved. But it was far too heavy for him to move. He obviously hadn’t thought this bit through. I almost wanted to laugh with relief. Except now the dragon fruit was pulsing a vivid green. The spiky skin started to ripple and I remembered the night Flicker had burst out of his fruit.

‘It looks like it’s going to erupt out of there,’ Kai said.

I nodded. ‘Get back, everyone!’

Liam stayed where he was, his eyes fixed on the fruit as it continued to swell. A grin spread across his face.

‘This dragon’s going to be epic!’ he shouted. ‘It’ll wipe the floor with your feeble squirt-sized dragons.’

He was acting like some kind of evil super-villain. I half expected him to rub his hands together, cackling gleefully.

And I guess he might have done, had the fruit not burst at that point and splattered him with huge quantities of green foul-smelling goo.

‘Slimed!’ cried Kai and Ted in unison and high-fived, looking utterly delighted as Liam staggered around covered in smelly gunge.

Meanwhile the dragon that had hatched from the fruit had passed in an arc over our heads. As we watched, it landed some way off. It was the size of a large turkey and was a fluorescent green, which made it look almost radioactive. It raised its head, unfurled its wings and shook its body. It shuddered and we all stared in horror.

‘It’s getting bigger!’ Kat cried.

The dragon was indeed growing. It had gone from turkey to large sow in a matter of seconds. And it didn’t look as if it was about to stop. With every shudder it expanded further, though its belly was inflating faster than the rest of it so its wings and tail now looked stubby in comparison.

Like Flicker when he was born, the dragon didn’t seem to have control over its tail, which flung about wildly, ripping through Grandad’s runner beans and sending his sweet peas flying. Its wings obviously weren’t up to getting it airborne, so it began to undulate its way across the garden, flattening everything in its wake.

When it had reached the size of a large, very fat walrus, it let out a rumble. A rumble that grew louder and louder until finally it opened its mouth and a green fiery belch exploded out of it. We all clasped our hands over our mouths and noses as the sickly green fog of belch breath drifted over us.

‘That stinks worse than Dexter after he ate that jar of chilli sauce,’ Kai groaned.

‘I thought Sunny was bad,’ Ted said. ‘That’s a whole other level of rankness.’

Liam, who was closest, stumbled around gagging, his face screwed up in disgust. His skin had taken on a green tinge of its own.

‘I bet it’s like skunk spray; he’ll reek of it for days.’ Kat grinned.

Liam wasn’t impressed. ‘It looks like a huge spiny winged slug,’ he whined.

‘Oh dear. Not living up to your expectations?’ Kat said sarcastically. ‘What a shame.’

He scowled at her and pulled a face. Then he picked up a strawberry that had been super-sized and was looking nicely fit to burst and lobbed it at her. It missed its target and splatted on the ground, but in reaching for another mushy missile Liam slipped, staggered backwards and actually bumped into the huge dragon’s rear end. Its tail swung up in the air and something truly noxious exploded out. If we thought the green gases from the front end were bad, they were nothing compared to this. It exploded out with such force that Liam was sent flying one way and the dragon actually lifted slightly off the ground and flew forward in the other.

‘That’s jet propulsion in action, that is,’ sniggered Ted.

The dragon seemed keen to capitalise on its first self-propelled flight of less than two metres. It had its eyes on Grim’s super-size aubergines and a flimsy wire fence wasn’t going to get in its way.

‘We’ve got to stop it,’ I cried.

But how could we? It was getting bigger by the second. And so were its fiery belches. One of the trunks of the apple trees had already been left blackened.

We tried to form a wall in front of it. But you try facing down a ravenous fire-belching dragon which is clumsier than you’d be after spinning upside down on a roundabout all afternoon. And there was no way any of us were going near its back end.

‘What are we going to do?’ Kat yelled.

They were all looking at me like I had some great plan tucked up my sleeve. I resisted shrugging helplessly and instead looked for Flicker, trying to buy myself a few seconds to think.

But a few seconds is all it takes for things to go from bad to very, very bad indeed. With another shudder the dragon gained elephant stature. And its next belch set light to Grim’s compost bins.

And then Kat squealed. And we all turned to see a tall figure striding down the garden through the darkness towards us.