Now the forest is dense enough for them not to be seen from above, and the immediate danger of Mrs Halloway has passed, Polly and Buster trundle more slowly through the trees. Polly looks out for slipper weeds, because her father once told her that if you suck them they can keep you going until you find water. Buster strides ahead, his monster senses on alert for a river or a stream.

When they were little, Polly’s father would often take her and her sister hiking through these woods on the outskirts of town, but she doesn’t remember them ever coming as far as this. Here, it is quieter than a forest should be. Only the stripey gizzbugs still whirr annoyingly around them, and Polly swats at one every now and then before they can land on her and sting.

Eventually, Polly thinks she spies a bunch of slipper weeds in the hollow of a gannery tree, its wide, fan-shaped leaves quivering in the breeze. She wanders over to look more closely, then hears a rustling in the branches. She looks up – but it is too late! Something leaps out from where it is hidden among the leaves and lands on Polly, pinning her to the ground.

‘Buster!’ she yelps, her heart leaping in her chest.

The face of the creature is so close to hers she can only see its bared yellow teeth.

‘Buster! Help!’ Polly screams again.

Within seconds, Buster is at her side. He plucks the creature from Polly as if it were only a squawling kitten. It claws at his face, and Buster has to turn his head and hold the creature away from him to avoid getting scratched.

Polly sits up to see what has attacked her and suddenly recognises who it is.

‘Maggie!’ she cries before Buster tosses the creature into the bushes. ‘Wait, Buster. Look! It’s Maggie!’

Buster plops the snarling monster back down onto the ground and peers at her more closely. His eyes grow wide with joy when he recognises the monster who lives with his family from time to time. Buster’s mother looks after broken monsters and monsters who have no other place to go, and Maggie is the most broken and lonely of them all.

‘Maggie!’ he says, picking up her scrawny frame again, this time to squeeze her into a ferocious hug. ‘Maggie! It’s me, Buster! And Polly. You remember Polly, don’t you?’

He places her down on the ground again, more gently this time, and she looks back and forth between them, her lined face crumpled in confusion. Her eyes light up when she recognises Buster. Polly, however, she seems to be having more trouble remembering – even when Polly holds up her grubby bandaged hand.

Maggie’s bite has almost completely healed, thanks to Miss Spinnaker’s magic potion, but Polly knows she still has to be wary. Buster’s mother has warned her that Maggie can sometimes lash out if she’s startled. But Polly knows this is only because Maggie has had a hard life, which has made her not right in the head. Buster’s mother has taught her that all monsters need love, even the most unloveable.

‘Maggie!’ says Buster. ‘What are you doing here? Did you run away? Where’s Mum and Dad? Are they with you?’ he asks. ‘Maybe they are out looking for us?’ he says to Polly, hopefully.

Maggie shakes her head. Then she stands up straight and pounds her chest with one scaly claw. Polly notices she is wearing a tight red vest over her old grey dress. On the top left pocket of the vest, just above her heart, there is an ‘M’ embroidered in gold.

‘M?’ asks Buster. ‘What’s that, Maggie? Is that M for Maggie? Did Mum make that for you?’

Maggie shakes her head again and scowls. She jabs at her chest with a bony finger and jabs at Buster’s, too. Then she glares suspiciously at Polly.

‘Oh,’ says Polly quietly. She has understood. ‘M is for monster.’

Buster chuckles. ‘Monster? Is that what the M is for? But we know you’re a monster, Maggie. What are you doing with an M on your shirt, wandering around in the woods out here on your own? Are you lost?’

Maggie shakes her head and rocks from side to side, angrily hissing and spitting at the ground in frustration.

‘I don’t think so, Buster,’ Polly says slowly. ‘I don’t think she’s alone. I reckon I know what that M stands for. It stands for Monsters Against Witches. I thought it was just witches ganging up against monsters, but maybe there are monsters out here forming a gang, too?’

Maggie grins proudly and nods her head. Then she snatches Polly’s arm and begins to drag her away.

‘Maggie, don’t be silly!’ Buster says gently. ‘What are you doing? You don’t have to drag Polly like that! Are there other monsters here in the woods? Is that where you are taking us?’

Maggie nods fiercely. But she shoos Buster away with one claw.

‘What?’ Buster says, puzzled. ‘You don’t want me to come?’

Maggie shakes her head. She is trying to look ferocious, but with her missing teeth and pot belly sticking out from under her vest, it’s hard to take her too seriously.

Polly turns to Buster. ‘I think she’s trying to capture me,’ she whispers. ‘That’s probably what she’s been told to do. We should go with her and talk to the other monsters. Once they know we’re on their side I’m sure they’ll help us out. They might even know what happened to Miss Spinnaker. She must have flown through the forest at some stage this morning.’

‘Oh,’ says Buster, now understanding Maggie’s plan – and Polly’s, too. He lopes along beside them. ‘Good work, Maggie! Those other monsters are going to be very pleased with you, aren’t they? Capturing a witch in the forest. You don’t mind if I come along as well, do you?’

Maggie pauses for a moment, her brow wrinkling as she considers this. Then she shrugs and nods and scurries off through the trees again, pulling Polly along behind her.