David nodded, but he did not feel reassured. In this land, it seemed that hunger inevitably overwhelmed cowardice, and the harpies of the Brood, as thin and emaciated as the wolves, looked very hungry indeed.

After they had walked for a little while, their footsteps echoed by the beating of the harpies’ wings, they saw a pair of bridges spanning the gorge. The bridges were identical. They were made from rope, with uneven slats of wood for the base, and they did not look terribly safe to David.

The Woodsman stared at them in puzzlement. “Two bridges,” he said. “There was only ever one bridge at this spot.”

“Well,” said David, matter-of-factly, “now there are two.” It didn’t seem like such a terrible imposition to have a choice of two ways to cross. Perhaps this was a busy spot. After all, there didn’t seem to be any other way to get across the chasm, unless you were able to fly and were prepared to take your chances with the harpies.

He heard flies buzzing nearby and followed the Woodsman to a small hollow just out of sight of the chasm. The remains of a cottage and some stables stood there, but it was clear that the property was deserted. Outside one of the stables lay the carcass of a horse, most of the meat already picked from its bones. David watched as the Woodsman peered into the stables, then looked through the open doorway of the house itself. With his head lowered, he walked back to David.

“The horse dealer is gone,” he said. “It looks as if he fled with whatever horses survived.”

“The wolves?” asked David.

“No, something else did this.”

They returned to the chasm. One of the harpies hung in the air nearby, watching them, her wings beating a fast cadence to keep her in place. She stayed in that position for just an instant too long, for suddenly her body spasmed and the barbed silver tip of a harpoon shot through her chest, a length of rope anchoring the shaft to a point lower down on the canyon wall. The harpy grasped the harpoon, as if she could somehow wrest her body from it and escape, but then the beating of her wings began to fail and she plummeted down, twisting and turning until the rope reached the end of its length and she was brought up short, her corpse striking against the rock with a dull, thudding sound. From the edge of the chasm, David and the Woodsman watched the dead harpy being hauled up toward a hollow in the wall, the barbs of the harpoon preventing the corpse from sliding off. Finally, the body reached the entrance to the cave and was pulled inside.

“Ugh,” said David.

“Trolls,” said the Woodsman. “That explains the second bridge.”

He approached the twin structures. Between them was a slab of stone into which words had been laboriously, if crudely, carved:

One lies in truth,

One’s truth is lies.

One path is death,

One path is life.

One question asked,

The path to guide.

“It’s a riddle,” said David.

“But what does it mean?” asked the Woodsman.

The answer quickly became apparent. David had never imagined that he might see a troll, although he had always been fascinated by them. In his mind, they existed as shadowy figures who dwelled beneath bridges, testing travelers in the hope of eating them when they failed. The figures that climbed over the lip of the canyon, flaming torches in their hands, were not quite what he had expected. They were smaller than the Woodsman but very broad, and their skin was like that of an elephant, tough and wrinkled. Raised plates of bone, like those on the backs of some dinosaurs, ran along their spines, but their faces were similar to those of apes; very ugly apes, admittedly, and ones that seemed to be suffering from severe acne, but apes nonetheless. Each troll took up a position in front of one of the bridges and smiled grimly. They had small red eyes that glowed sinisterly in the gathering darkness.

“Two bridges, and two paths,” said David. He was thinking aloud, but he caught himself before he gave anything away to the two trolls and resolved to keep his thoughts to himself until he had come to some conclusion. The trolls already had all the advantages. He didn’t want to give them any more.

The riddle clearly meant that one bridge was unsafe, and to take it would lead to death, at the hands of either the harpies or the trolls themselves, or, assuming both parties failed to act quickly enough, by falling a very long distance and landing hard on the ground below. Actually, David thought both bridges looked pretty ramshackle, but he had to assume that the riddle had some truth to it, otherwise, well, there was hardly any point in having a riddle at all.

One lies in truth, one’s truth is lies. David knew that one. He’d encountered it somewhere before, probably in a story. Oh, he had it! One could tell only lies, and the other could tell only the truth. So you could ask one troll which bridge to follow, but he-or she, as David wasn’t entirely sure if the trolls were male or female-might not be telling the truth. There was a solution to it as well, except that David couldn’t remember it. What was it?

The light faded entirely at last, and a great howling arose from the forest. It sounded very close.

“We have to cross,” said the Woodsman. “The wolves have found our trail.”

“We can’t cross until we’ve chosen a bridge,” explained David. “I don’t think those trolls will let us pass unless we do, and if we try to force our way through and choose the wrong one-”

“Then we won’t have to worry about the wolves,” the Woodsman said, finishing the sentence for him.

“There’s a solution,” said David. “I know there is. I just have to remember how it goes.”

They heard a thrashing in the woods. The wolves were drawing ever nearer.

“One question,” muttered David.

The Woodsman hefted his ax in his right hand and with his left drew his knife. He was facing the line of trees, ready to take on whatever emerged from the woods.

“Got it!” said David. “I think,” he added, softly.

He approached the troll on the left. It was slightly taller than the other, and smelled slightly better, which wasn’t saying much.

David took a deep breath. “If I asked the other troll to point to the right bridge, which bridge would it choose?” he asked.

There was silence. The troll knit its brow, causing some of the sores upon its face to ooze unpleasantly. David didn’t know how recently the bridge had been constructed, or how many other travelers had passed this way, but he got the feeling the troll had never been asked that question before. Finally, the troll seemed to give up trying to understand David’s logic and pointed to its left.

“It’s the one on the right,” said David to the Woodsman.

“How can you be sure?” he asked.

“Because if the troll I asked is the liar, then the other troll is the truth teller. The truth teller would point to the correct bridge, but the liar would lie about it, so if the truthful one would have pointed to the bridge on the right, then the liar would lie about it and tell me that it was the one on the left.

“But if the troll I asked has to tell the truth, then the other is the liar, and he would point to the wrong bridge. Either way, the one on the left is the false bridge.”

Despite the approach of the wolves, the presence of the bewildered trolls, and the shrieking of the harpies, David couldn’t help but grin with pleasure. He’d remembered the riddle and recalled the solution. It was like the Woodsman had said: someone was trying to create a story and David was a part of it, but the story was itself made up of other stories. David had read about trolls and harpies, and lots of old stories had woodsmen in them. Even talking animals, like the wolves, cropped up in them.

“Come on,” said David to the Woodsman. He approached the bridge on the right, and the troll standing before it stepped to one side to allow David to pass. David put a foot on the first of the boards and held on tight to the ropes. Now that his life depended on his choice, he felt a little less certain of himself, and the sight of the harpies gliding just beneath his feet made him even more anxious. Still, he had chosen, and there was no going back. He took a second step, then another, always keeping a grip on the rope supports and trying not to look down. He was making good progress when he realized that the Woodsman was not following. David stopped on the bridge and looked back.