A breeze – warm and pine-scented – swept through the trees and rustled a whispered welcome from the bracken. Wells of sunlight sank through the thick canopy of leaves, spreading a golden glow over the moss-carpeted ground, whilst floating pollen explored the morning air, twinkling in the dappled light like tiny, floating stars.

‘This is definitely a place of magic,’ said Archie, his skin tingling.

They soon found a path and, using the map illuminated by the magic lantern, carefully trod their way through the old forest. Tree roots carved up the earth beneath their feet or sometimes stretched out of the ground to make archways and tunnels. Sherbet ran ahead, occasionally diving into clumps of ferns to chase after squirrels (which were far too canny to be caught by a silly, clumsy dog).

‘It’s really quiet,’ whispered Fliss. ‘Eerily quiet.’

At that moment, there was a crash as Billy tripped over a root and landed in an undignified heap. A startled pheasant shot into the air, scolding the visitors.

‘It was eerily quiet,’ said Fliss icily. ‘Do you need help putting one foot in front of the other, Billy?’

‘It’s all these tree roots – they must come from the Wyrdie Tree.’ Billy picked himself up and dusted pine needles from his knees. ‘I was trying to take notes as we walked. I want to document as much of this expedition as I can.’

‘Just be careful!’ said Archie sharply. He had the same feeling of being watched that he had sensed the day before. He didn’t want to attract any more attention than was necessary.

After they had been walking a while, they noticed it was getting darker.

‘The branches are making a roof over our heads,’ said Fliss, pointing upwards.

‘The trees are changing,’ said Billy. ‘It’s certainly getting wyrdier!’

The trunks around them had grown into hunched, hulking shapes, boughs twisted and knotted into sinewy limbs, twigs spreading into spindly fingers. The craggy bark was cracked into the features of ancient, wrathful faces, bearded with lichen.

‘It’s like we’re surrounded by my grandpa and his bowling buddies,’ said Billy. ‘They look like that whenever they lose a game.’

‘I wonder why they’re so angry-looking?’ said Fliss. ‘Maybe they don’t like visitors.’

Archie was reminded of his dream and shivered. The atmosphere had become oppressive, and the bracken tugged at his feet and made him stumble. He began to feel the dread grow inside him once more, only this time it was worse and getting stronger by the second. A thick mist seeped between the trees, turning their trunks into pale, misshapen ghosts.

Archie stopped, suddenly filled with fear. In the distance, he could make out a hunched silhouette stalking through the gloom. He grabbed Sherbet and hid behind a tree, gesturing to the others to do the same. The dog whimpered quietly. He seemed to know this was not the time for barking. They held their breath and watched as the dark figure crept closer. A buzzing, whirring sound followed it as it moved, as if it were being escorted by an army of insects. Then the creature stopped.

It was cloaked. The hood slowly turned towards them, its hidden eyes searching. Archie ducked back behind the tree trunk, clutching Sherbet tightly.

Does it know I’m here? he thought, his head aching and sweat beading on his forehead. Can it sense me, like I can sense it?

The figure paused for several, horrible, silent seconds. Then, with a soft, stealthy movement, it continued on its way. It disappeared into the forest depths, and the strange insect-like sounds faded, along with the unnatural mist.

Fliss spoke first.

‘What was … that?’ she hissed. Billy was huddled on the ground, trembling.

‘A doom wight!’ he said. ‘Or maybe a bracken beastie. Or a forest fungalfreak? Whatever it was, I think I might have to invent a new Macabre Creepy Scale – that was worse than … than Auntie Doreen, with the moustache!’

Archie was quiet, relieved that the feeling of dread – and his headache – were lifting. Was that the Mirk? he thought. Just its very presence had filled him with terror.

To one side, he spotted a clearing in the forest. A patch of blue sky was visible through the leafy roof.

‘Let’s stop there for a break,’ he suggested. The others readily followed him as he led them off the path. But when they reached the clearing, they found it was far from being a pleasant spot for a picnic. Ragged tree stumps scarred the area like yellowed teeth, and the trampled ground was thick with drifts of fresh sawdust. It was desolate and dead. Sherbet sniffed the floor and whined.

‘Someone’s been cutting down the trees!’ said Fliss.

‘No wonder this part of the forest looked so angry,’ said Archie, running his hand over the sawn surface of a stump, as if stroking a wounded animal. ‘It’s been attacked!’

‘Vandals!’ said Billy. ‘Do you think it was that scary person?’

‘Maybe,’ said Fliss thoughtfully. ‘This was done with man-made tools.’

‘Let’s get moving,’ Archie said in a hushed voice. Without another word, they returned to the path.

The map guided them deeper into the forest. The air cooled and became fresher as they travelled, the heavy atmosphere left behind with the scars of the clearing, and walking became much easier. The land began to rise, and suddenly the forest ended. They found themselves on a grassy mound. Immense, moss-mottled stones edged the rise, carved with pictures and strange letters. At the centre of the stone circle, crowning the top of the mound, stood a tree.

‘Now that,’ said Fliss, ‘is very definitely a tree. With a capital T.’

‘It’s the Clan Chief of all the trees!’ said Billy.

‘This is it!’ said Archie, swallowing hard. ‘We’ve found it. It’s the Wyrdie Tree.’