Kai was right to be dubious. Every morning we passed Liam’s house and took a peek, hoping we might find a way to sneak in unseen. But Liam’s mum worked from home, so even when Liam had football after school we couldn’t get near the place.

Luckily though, a few days later, I got my chance when Mum asked me for ‘a really big favour’. The ferrets had been partying in the kitchen cupboards and thanks to the mess – and trying to find the sneaky pair – she was late to pick Lolli up from a play date.

‘Could you pop and get her, love? I wouldn’t normally ask, but Finnegan is still hiding somewhere and I daren’t just leave. It’s only round the corner. She’s at Bea’s house.’

Any other time I would have moaned, groaned and down right refused this request. Not because I minded fetching Lolli, but because of where she was. The one house I’d usually go out of my way to avoid. But not today. You see, Bea was Liam’s little sister.

This was a brilliant chance to get a closer look at the shed. When I got to the house, instead of knocking on the front door I headed for the side gate. If anyone asked what I was doing I could just say I was coming round to the back door.

When I popped my head round the wall and scanned the garden I saw Bea and Lolli playing in a big turtle-shaped sandpit. They had built a castle and were now decorating it with stones and sticks. A doll with no hair was propped up against one wall and Bea was holding a little pony, cantering it up to the drawbridge. Meanwhile, Lolli waggled a shark along the moat they had dug, making chomping noises as it chased the pony.

Suddenly Liam came out of the shed. He laughed when he saw the girls’ castle and I thought for a second he was about to kick it to pieces. But then I realised he didn’t need to. Because he opened his jacket and the grey dragon flew out. It flapped round and round above Bea’s head. She sat there open-mouthed, while Lolli waved the shark at Liam and gave him her hardest stare.

What was Liam thinking? Anyone could be watching from the house. But of course he was too busy showing off to care.

‘What this fairy story needs is a dragon,’ he said nastily. The dragon swooped lower and let out a blast of green. Bea twisted out of the way and fell backwards, landing on the castle and squashing it flat.

Both girls immediately burst into tears. I raced over and glared at Liam, who was so surprised to see me materialising in his garden that he nearly fell in the sandpit too.

‘What are you doing here?’ he spluttered.

‘Keeping an eye on you, that’s what!’ I snapped. ‘And just as well, by the looks of it. Why do you always have to cause trouble?’

Liam scowled. ‘Listen up, ant-boy,’ he said, getting to his feet so he could properly tower over me. ‘I can do what I like.’ He brushed the sand off his trousers before squaring up to me. ‘In fact, I can do whatever I like. Whenever I like. Wherever I like. And there’s nothing you can do about it.’

I felt myself bristling. ‘Oh yeah? You’d better watch out, we’re onto you. Whatever it is you’re planning.’

‘You think so, do you?’ Liam snorted. ‘It doesn’t matter what I’m planning. I can do anything I want now. You can’t tell on me ever again.’

He leaned in close till I could smell his cheese-and-onion-crisp breath and said, ‘Because I know your secret.’

Then he looked up at the sky as if searching for something. And I suddenly felt very glad I’d left Flicker at home.

Liam lowered his voice, going for the full-on evil baddie hiss. ‘And I can tell everyone any time I want. So you’re the ones who’d better watch out.’

Walking home with Lolli, I couldn’t help thinking how complicated life was since the arrival of the dragons. It was all getting rather difficult, what with making sure the dragons stayed out of sight, clearing up unexploded poo, hiding any claw marks and burn marks, oh and in my case keeping an eye on two sneaky ferrets.

Then there was the very real worry of whether the dragon-fruit tree would even survive. And now there was Liam and whatever he might be planning and how we were going to distract him long enough to rescue his dragon. And of course, whether we could do it at all without him giving the whole secret away.

That’s an awful lot to think about, I can tell you. Just something to bear in mind, if you’re someone who likes things simple. Because having a dragon isn’t all playing games and toasting marshmallows – there really is more to it than that!

To deal with one of those worries – the state of the dragon-fruit tree – I made sure that every day I got over to Grandad’s to sprinkle the five spoonfuls of ash on it. I was tempted to chuck a whole load on at once, but I kept to the instructions Elvi had left. The last thing I wanted to do was make it worse. It was bad enough knowing I hadn’t managed to look after it properly – what if it actually died under my care?

I thought it was making a difference. The leaves seemed to be getting greener and less limp, and even the shrivelled fruits looked as if they might be fleshing out. But it was hard to tell – it still didn’t look very healthy.

But then Ted told me something that made me realise we were going to need more than ash to save the tree.

‘Well, Dad’s been asked to take photos of the County Flower and Veg Show, you know, for the paper. And while we were out he got talking to one of the old guys who was entering. And he said he didn’t know why he was bothering really because he never won anything. Everything he tried to grow just shrivelled up. And it was always the same old story of this one guy winning. And here’s the interesting bit,’ and Ted leaned in ready to whisper, ‘he reckons this guy is using sprays and all that sort of stuff, which is dead illegal in these competitions. And he even said he wondered if someone hadn’t been tampering with his plants. And guess who he was talking about?’

Ted gave me a meaningful stare. But I already knew.

‘Grim!’ I said.

It had to be. Suddenly it all made sense. Hadn’t he been the one moaning about pesky bugs? Then there were those boxes he was hiding, his fortified shed and, most incriminating of all, the way he’d been creeping about in the middle of the night.

‘Grim’s cheating!’

‘More than that,’ Ted said. ‘He’s sabotaging the competition to make sure he can’t lose.’

The nerve of it! After all his accusations and wagging fingers, accusing us of doing things we shouldn’t.

What’s more, with his garden so close to Grandad’s, the state of the tree made sense too. He was killing it with chemicals. Whether he actually meant to damage the tree or not, it didn’t matter. He was using them. It wasn’t my fault after all. It was Grim’s.

No wonder the ash hadn’t been working! The poor tree didn’t stand a chance.

‘We need to get a closer look at what’s in Grim’s shed,’ I said. ‘We need proof.’

Because I wasn’t about to let anything happen to the tree. It was up to me to protect it. And I intended to do just that.