He immediately lost his hold and slid helplessly down, deep into the bowels of the ancient tree. Deeper than ought to be possible, so that his slide seemed to take him down into the very hill and even further, beneath every field and forest of the living. Down, perhaps, even into the realm of the dead...

Before that thought had time to send him into a panic, the slide ended, sending him sprawling onto a floor of packed earth. Blinking like an owl, he looked around the little chamber he had landed in.

It was no more than two fathoms across in every direction, a little less in height and lit by glowing strands that flowed over the walls like roots. The walls were of packed deep soil, dark and moistly gleaming, while the floor was a dry, ruddy dirt. Behind him, next to the hole he had come from, a smooth, flat and perfectly round slab of granite sat in the wall. Before him, an archway opened into a tunnel that wound away or of sight.

On each side of the archway, a huge root stood as if on guard. They stretched one arm each above the arch, meeting in the middle, as if holding up a curtain. On the other side of each root, another limb bent out, also like an arm but longer and ending in a sharp point, as if holding a short spear against trespassers. The more he looked, the more Robird saw details in the roots - legs, shoulders, faces, eyes...

It was impossible to tell which way the root guards' eyes looked. Yet he felt certain they watched him, appraising him. It was also hard to tell which way the points of their root-spears were aimed, but the itch on his breast, just over his heart, did not bode well.

One look up the shaft he had slid down and a few moments of hard pushing and pulling on the slab told him that the only way from here went past those sharp points. He faced them indecisively.

"The... the king has summoned me. Please, may I pass?"

Though nothing moved, a flitter of attention seemed to wash across the seeming faces of the roots. Still nothing moved, yet the itch on his breast subsided. Taking it as a good omen, he bowed and thanked the guards and passed underneath their upraised arms.

As soon as he was through, a sharp rustle made him turn around to stare straight into a compact wall of soil where the arch had been. Squaring his shoulders, he faced forward again, into the tunnel winding away before him, still lit by root threads, and walked on.

The tunnel soon spilled out into a great cavern. The floor sloped gently downwards like a shallow bowl, with steps hewn out of rock leading down the first five fathoms or so from where he stood. A straight path went from the foot of the stair towards the centre of the cavern, where an immense tree trunk seemed to support the domed ceiling far above. Just how far was hard to say, since a thick tangle of roots or branches hung down from it - branches, Robird decided, since they were thick with golden, glowing oak leaves, filling the cavern with a warm autumn light. But the lowest leaves were at least a dozen fathoms above his head so the ceiling, he guessed, ought to be at least half that height again.

On the roots of the great tree a throne was carved or grown. It was occupied by a figure looking just as he had always imagined the oak tree as a king. A slender wreath of oak leaves lay about his head, shining just like the foliage above. Amber, smouldering eyes looked out from a stern, grey-bearded face underneath bushy eyebrows. In his hand was a sceptre made out of a gnarled, deeply polished oak branch and his robes shimmered like satin in all the browns and greens of the forest.

All around him were courtiers, attired in similar fashion. But Robird barely heeded them, since his eyes were drawn to the woman on the seat that was formed by the root, just a little lower and to the right of the throne.

She was the most beautiful he had ever seen. Her straight back and bare shoulders gave the impression of great strength that turned his knees weak. The green eyes shot glances of stern aloofness at him, sending shivers down his spine, while her reddish brown mane, forcibly tied back behind her head, gave her an impish look that set his heart pounding. A strange emotion never felt before gripped him, that was as much overpowering fear as it was an irresistible yearning. Fearning, he would later call it to himself, thinking back with a clearer mind on the moment he first saw her.

But there, inside the moment, all thought abandoned him at the sight and he stood still and dumb as a doorpost, gaping and blinking.

"Descend."

Whether the voice uttering that single command came from the immense trunk itself or from the figure on the throne at its feet, it was the same voice as that of the oak, though a hundred times richer and stronger. As his feet obeyed without asking his head, he trod down the steps as if in procession, while he wondered to himself if the great oak on the hill was merely the top of this huge tree - perhaps indeed the world tree, if such there was.

But he knew as he came closer that he would never have the nerve to ask. The eyes of the king were not hostile, but hard and distant, watching him as a farmer resting in the shade might watch the flies about the cowpat.

Still, this king had both offered and asked of him help, placing him at least somewhat above a fly on dung. Robird fought hard not to stare at the enthralling woman - the oak princess, he thought to himself - and keep his wits about him for whatever was to come.

Stopping before the oak king, he bowed with the same flourish as ever.

"Here I am now, your majesty."

The king nodded slightly and his lips twitched into a brief, sardonic grin.

"Indeed you are. We are pleased. You may lay aside those titles of you wish, I make no claim to them."

Robird frowned.

"Are you not king, then? But..."

"You see me as such only because you always did. If trees had kings, I might be the one. We don't."

Nodding slowly, then shrugging, Robird continued.

"I will call you king then but leave out the rest. I have no other name for you."

"As you please," the king answered, mirroring Robird's shrug. Then he leant forward, propping one elbow against the knee and squinting at the visitor. "So you passed our first test."

Robird kept his face blank.

"Test, king?"

"Our guards. You could not have passed them alive without invoking me and asking leave. You proved that you can see beyond the apparent and that you are not presumptuous."

"My dear king," Robird sighed, "I am the third son of a poor vilein, as well you know. I would be a fool... well, an even greater fool to believe I had anything to be presumptuous of."

The king made that sound as if laughing or sneering, Robird could still not say which.

"There are fools and fools. You are at least not of the hopeless kind."

The princess huffed quietly and looked away. The king glanced at her.

"My daughter is not likewise convinced."

That strange fearning returned in full force. It was all Robird could do to keep from wincing.

"To be honest, neither am I," Robird managed at last. "Yet you summoned me for a reason, king. If this fool of whatever kind may offer you any help and be helped in return, I would be glad to hear how."

This time, the sound the king made seemed more like laughter, though none of the jolly kind.

"In due time, my fool. But first, perhaps my daughter would deign to sing for us?"

The princess was at first so quiet and still that Robird thought she would refuse. Then she heaved a sigh longer and deeper than he thought possible, before finally rising from her seat. She placed herself before her father, facing Robird without looking at him. Instead she raised her eyes to the golden glow of the ceiling and raised her arms towards it.

Robird's breath caught at the sight, but what came next left him gasping like a fish on land. For if this was song as he thought of it, then a cup of the gods' own nectar was a thimbleful of stale water.

If there was a tune in it, it was none that his ears could hear. Instead, it seemed to him that he listened to the voice of the forest, that he had often imagined hearing in the wind and rain through the leaves, the multitude of bird songs, the murmur of brooks and streams and the scurrying, scampering and buzzing of little creatures.

Yet this was not the mindless, self-indulgent babble that he was used to. This was a song of long and slow purpose and brooding patience. It echoed in his mind a life of centuries, where seasons passed like days and growth and decay were like breaths. He knew that if he listened long enough, if he could understand the meaning of what he heard, all those questions that kept blooming in him, those that he had learnt from uttering them too often were merely silly notions that distracted him from work, would be answered.

Then he noticed that all the courtiers were dancing. Each had their own dance, without any likeness to that of the neighbour. Still they harmonised and formed together a single dance, like the elaborate dances that the landlord held at his court but infinitely more varied. Some dances were peaceful, thoughtful, others powerful, belligerent, still others quirky and playful...

And as the song gently ended, it dawned on him.

"You are all oaks!"

All eyes turned to him and he blushed, hoping that oaks could not tell a blush.

"I know you from your dances. You!" He gestured at a nearby courtier. "Are you not the young oak at the end of the trail to the manor? And you..." he turned to another. "I am sure you are the one just outside our pig fen. You know, a very small fen with just one sow in it? There's an old cherry next to you."

The courtiers said nothing but looked quizzically at the king, who in turn grinned and looked at his daughter. She was actually looking straight at Robird now, scowling.

"Well, daughter?"

And finally the oak princess spoke. Her voice was deep, though not as deep as her father's, and though it had a similar creaking tone, it was smooth and somehow lush in comparison.

"I grant you that he is an unusual and insightful fool. But he has not yet revealed what he made of my song."

"Oh, lady!" Robird exclaimed and went down on his knees. "If I could spend a hundred years just listening to that song and learning from it, I would be a lucky man. It makes me wish I were an oak!"

And for the first time, the look in her eyes on him was not distant and cold. Instead, a doubt and a reluctant curiosity seemed to glimmer there.

Then she turned and walked slowly back to her seat, carefully sitting down and staring once more into the distance.

"It is still not my wish."

Robird rose again, brushing dust off his knees in consternation.

"I don't understand, my lady. Do you mean it's not your wish that I should be an oak?"

And the oak princess laughed, sending a feeling into Robird's heart that felt as if he were lying on his back on a glorious, leisurely homage day without a care in the world, just studying the sunlight playing in the leaves above him.

"If you were an oak, it might have been my wish but not my father's and this whole farce would never have been staged. Father, please explain to the fool and have done with it."

"Yes," the king agreed, "the time is due." He turned to Robird. "I will be brief now and you can ask later. You dream of a better life, while humans are destroying my realm faster than ever. I need a human with the power and will to protect us..."

"Please, king, I have the will but not the power to do that..."

"I know. Do not interrupt."

Robird bowed quietly.

"My wish is that my daughter bears you a son who will be our protector, and who will make you a man of wealth and renown."