Yet their figures had always contained uncertainty. The fact that their calculations might be off by a few steps was not relevant, but not knowing their precise starting point was. They had entered the surface building from the west. But the confusion surrounding their flight and the destruction of the gremlin-built structure made it impossible to know how many steps Valiha had covered before coming to rest. And when things had quieted down, the top part of the stairs had been clogged in rubble.

"You don't think she ran through half a revolution, do you?" he said at last.

"I don't think so. But she might have. If she did, this tunnel leads to Phoebe, not Thea."

Chris wished he could put it out of his mind. Their situation was so precarious; it depended on so many factors beyond his control. It was possible that even if they reached Thea-who Cirocco had said was a friendly region-she would not be kindly disposed to three invaders of her realm.

"We'll face that problem when we come to it," he said.

Robin laughed. "Don't give me that. If Phoebe is at the other end of this tunnel, what we'll do is sit down and starve to death."

"Don't be such a pessimist. We'd die of thirst long before that."

The tunnel began gradually to widen, to look less like an artificial passageway and more like a natural cave. Though there were more of the glowbirds, their light was correspondingly less effective in the larger space. Chris saw branch tunnels to the north and south, but they both felt it made better sense to continue in the direction they hoped was east.

"Valiha must have still been panicked when she came through here," Robin said. "I presume she would have kept going straight. If she'd started to think again, I'd expect her to come back for us, or wait, before she started exploring the side tunnels."

"I agree. But I didn't expect her to come this far. And I keep remembering she's got all our food and water. I could sure use a drink."

The cave floor had become irregular. They found themselves going up and down gentle slopes that reminded Chris of the sand dunes they had traversed on the surface of Tethys. The roof was by then so distant that the glowbirds clinging to it looked like stars turned orange by atmospheric haze. Little detail could be discerned above, and only the general shapes of things on the ground. When they heard running water, they approached it cautiously until the stream betrayed itself by coppery reflections. Chris dipped a finger in it, ready to wipe it dry if it proved to be acid. When he was not burned, he raised some to his lips. It had a faintly carbonated taste. They removed their shoes and waded, found that it was only ten meters across and never more than half a meter deep.

Beyond the stream the ground changed character again. They could see jagged spires rising around them. Once Chris fell over a two-meter drop. For an eternal second he did not know if the fall might be his last moments of life, until he hit on his hands and knees, cursing loudly more from relief than anger. He had a few bruises to add to his cuts and scrapes but was otherwise uninjured. His increased caution after the scare paid off quickly. Reacting more from instinct than any sure knowledge, he found himself reaching out to stop Robin. When they moved forward more carefully, they saw she had been no more than a meter from a precipice that tumbled down thirty or forty meters.

"Thanks," Robin said quietly. He nodded, distracted by a glow to his left. He was having no luck making it out when he heard the sound. Someone was singing.

They moved toward the light. As they did, detail emerged from the endless shades of gray and black. Shapeless blurs became rocks, dark traceries like the webs of spiders turned into emaciated vines and shrubs. And the light could be seen to flicker like a candle. It was not a candle, but the lamp Valiha had been carrying in her saddlebag when she took flight. In one last clearing of perceptions he could see one of the shapes near the light was Valiha herself. She was on her side, lying on the far slope of the small canyon twenty meters from the bottom. He called out to her.

"Chris? Robin?" she shouted back. "It is you! I've found you!" He thought it an odd thing to say but did not dispute her. He and Robin picked their way down the slope on their side, then climbed to her position. It seemed a strange place to rest. Another twenty meters, and she would have been on level ground. He had suspected something was wrong, and now he was sure of it. There was something about her that reminded him, with a flash of fear, of Psaltery lying in his blood-soaked dying ground.

When they reached her, the light of the lamp showed her face smeared with dried blood. She sniffed loudly and drew her hand across her upper lip.

"I'm afraid I've broken my nose," she said.

Chris had to look away. Her nose was broken, and so were both her front legs.

Robin sat quietly twenty meters from Chris and Valiha and listened to him shouting at the Titanide. Valiha had suggested, shortly after he determined just how bad her injuries were, that they might as well put her out of her misery. Chris had exploded.

Her body grew heavier each minute. Soon she would be one with the rocks and the darkness. It would be a relief. It would mean an end to frustration. She now realized her momentary elation after their escape from Tethys had been a mistake. She would not make it again.

But she could see that Chris wasn't going to make it easy. He still thought there were things they could do. He was coming toward her now, and she felt sure he wanted to make plans.

"Do you know any first aid?" he asked.

"I can put on a Band-Aid."

He grimaced. "That about sums it up for me, too. We're going to have to do more than that, though. I found this." He opened the leather case he carried. Its sides folded out in all directions, lined with pouches and compartments. Metal glinted in the light of his lamp: scalpels, clamps, syringes, needles, all neatly laid out for the amateur surgeon. "One of them must have known how to use this stuff, or they wouldn't have brought it along. Valiha says Hautbois had a lot more. It looks to me like there's enough equipment here to perform minor surgery."

"If you know what you're doing. Does Valiha need surgery?"

Chris looked tortured.

"She needs some kind of sewing up. Both breaks are in the ... what do you call it in a horse? Between the knee and the ankle. I think just one of the bones is broken in her right leg; she can't walk on it anyway. But the left leg is bad. She must have taken most of her weight on that one. Both bones snapped, and one of the edges broke through the skin." He had picked up a slim booklet. "It says here that's a compound fracture, and the problem with it is usually fighting infection. We'll have to set the bones, clean out the wound, and sew it up."

"I don't really want to hear about it. You figure it out, and when you understand it, call me and tell me what you want me to do. I'll do it."

He did not respond for a while. When she looked up, she found him studying her face intently.

"Is there something wrong?" he asked.

She could not even laugh. She thought of mentioning that they were lost five kilometers underground in the dark with little food and less light and a demented demi-God to the east and west and an injured companion too big to carry to safety even if they could find their way out in the first place, but why spoil his day? Besides, that wasn't what he meant and she knew it and she was certain that he knew it, too, but she wasn't going to talk about it. Not ever.

So she shrugged tiredly and looked away from him.

He continued to look at her for a long time-it was as if she could feel his gaze on her, and how could he not know?-then reached over and put his hand on her knee briefly.