"If I can explain-" She paused as if looking for an answer we might understand. "My father says I should tell you that we have changed ourselves since the clones came back to colonize the dead Earth.

We have altered the genes and invented the nanorobs."

"Nanorobs?"

She paused again, staring at the far-off elephants.

"My father calls them artificial symbiotes. They are tiny things that live like bacteria in our bodies but do good instead of harm. They are partly organic, partly diamond, partly gold. They move in the blood to repair or replace injured cells, or regrow a missing organ. They a.s.sist our nerves and our brain cells."

The food forgotten, we were staring at her. A picture of innocent simplicity in the simple skirt and blouse and floppy hat, she was suddenly so frightening that I trembled. She reached to put her small hand on mine before she went on.

"My father says I should say they are tiny robots, half-machine and half-alive. They are electronic. They can be programmed to store digital information. They pulse in unison, making their own waves in the brain and turning the whole body into a radio antenna. Sitting here speaking to you, I can also speak to my father."

She looked up to smile at me, her small hand closing on my fingers.

"Mr. Dunk, please don't be afraid of me. I know we seem different. I know I seem strange to you, but I would never harm you."

She was so charming that I wanted to take her in my arms, but my awe had grown to dread. We all shrank from her and sat wordless till hunger drove us to attack the fruit and cakes again. Pepe began asking questions as we ate.

Where did she live?

"On that hill." She nodded toward the west, but I couldn't tell which hill she meant. "My father selected aplace where he could look out across the memorial."

Did she go to school?

"School?" The word seemed to puzzle her for a moment, and then she shook her head. "We do not require the schools my father says you had in the prehistoric world. He says your schools existed to program the brains of young people. Our nanocoms can be programmed and reprogrammed instantly, with no trouble at all, to load whatever information we need. That is how I learned your English when I needed it."

She smiled at his dazed face and selected a plump purple berry for herself.

"Our bodies, however, do need training." Delicately, she wiped her lips on a white napkin. "We form social groups to play games or practice skills. We fly our sliders all around the Earth. I love to ski on high mountains where snow falls. I've dived off coral reefs to observe sea things. I like music, art, drama, games of creation."

"That should be fun." Pepe's eyes were wide. "More fun than life in our tunnels on the Moon." His face went suddenly dark. "I hope your father doesn't send us back there."

"He can't, even if he wanted to." She laughed at his alarm. "He's finally done with the excavation. The charter site is closed and protected for future ages. All intrusion prohibited."

"So what will he do with us?"

"Does he have to do anything?" Seeming faintly vexed, she looked off toward the station dome on the crater ridge. "He says he has no place ready for you, but there are humanoid replicates playing your roles there in the Tycho simulation. I suppose you could replace them, if that would make you happy."

"Pretending we were back on the Moon?" Casey turned grim. "I don't think so."

"If you don't want that-"

She stopped, tipped her head as if to listen, and began gathering the water bottle and the rest of the fruit into the basket. Anxiously, Pepe asked if something was wrong.

"My mother." Frowning, she shook her head. "She's calling me home."

"Please!" Casey begged her. "Can't you stay a little longer? You are the only friend we've found. I don't know what we can do without you."

"I wish I could help you, but my mother is afraid for me."

"I wondered if you weren't in danger." He glanced out across the valley. "We saw a lion. Your really shouldn't be out here alone."

"It's not the lion." She shook her head. "I know him. A wonderful friend, so fast and strong and fierce."

Her eyes shone at the recollection. "And I know a Bengal tiger. He was hiding in the brush because he was afraid of people. I taught him that we would never hurt him. Once he let me ride him when he chased a gazelle. It was wonderfully exciting."

Her voice grew solemn.

"I'm glad the gazelle got away, though the tiger was hungry and very disappointed. I try to forgive him, because I know he has to kill for food, like all the lions and leopards. They must kill, to stay alive. Mymother says it is the way of nature, and entirely necessary. Too many grazing things would destroy the gra.s.s and finally starve themselves."

We stared again, wondering at her.

"How did you tame the tiger?"

"I think the nanorobs help me reach his mind, the way I touch yours. He learned that I respect him. We are good friends. He would fight to protect me, even from you."

"Is your mother afraid of us?"

She picked up the basket and stood shifting on her feet, frowning at us uncertainly.

"The nanorobs-" She hesitated. "I trust you, but the nanorobs-"

She stopped again.

"I thought you said nanorobs were good."

"That's the problem." She hesitated, trouble on her face. "My mother says you have none. She can't reach your minds. You do not hear when she speaks to you. She says you don't belong, because you are not one of us. What she fears-what she fears is you."

Speechless, Casey blinked at her sadly.

"I am sorry to go so soon." With a solemn little bow for each of us, she shook our hands. "Sorry you have no nanorobs. Sorry my mother is so anxious. Sorry to say good-bye."

"Please tell your father-" Casey began.

"He knows," she said. "He is sorry you came here."

Walking away with her basket, she turned to wave her hand at us, her face framed for a moment by the wide-brimmed hat. I thought she was going to speak, but in a moment she was gone.

"Beautiful!" Casey whispered. "She'll grow up to be another Mona."

Looking back toward the copied monuments of the old Earth, the copied station dome shining on the copied Tycho rim, I saw a dark-maned lion striding across the valley toward the pool where the elephants had drunk. Three smaller females followed. None of them our friends. I shivered.

5.

We wandered on up the valley after Tling left us, keeping clear of the trees and trying to stay alert for danger or any hint of help.

"If Sandor lives out here," Casey said, "there must be others. People, I hope, who won't take us for robots."

We stopped to watch impala drinking at a water hole. They simply raised their heads to look at us, but fled when a cheetah burst out of a thicket. The smallest was too slow. The cheetah knocked it down andcarried it back into the brush.

"No nanorobs for them," Pepe muttered. "Or us."

We tramped on, finding no sign of anything human. By midafternoon, hungry and thirsty again, with nothing human in view ahead, we sat down to rest on an outcropping of rock. Pepe dug a little holo of Tanya out of his breast pocket and pa.s.sed it to show us her dark-eyed smile.

"If we hadn't lost the radio-" He caught himself, with a stiff little grin. "Still, I guess we wouldn't call. I'd love to hear her voice. I know she's anxious, but I wouldn't want her to know the fix we're in-"

He stopped when a shadow flickered across the holo. Looking up, we found a silvery slider craft dropping to the gra.s.s a few yards from us. An oval door dilated in the side of it. Tling jumped out.

"We found you!" she cried. "Even with no nanorobs. Here is my mother."

A slender woman came out behind her, laughing at Pepe when he tried to repeat the name she gave us.

"She says you can just call her Lo."

Tling still wore the blouse and skirt, with her wide-brimmed hat, but Lo was nude except for a gauzy blue sash worn over her shoulder. As graceful and trim, and nearly as s.e.xless as Sandor, she had the same cream-colored skin, already darkening where the sun struck it, but she had a thick crown of bright red-brown curls instead of Sandor's cap of sleek fur.

"Dr. Yare." Tling spoke carefully to let us hear. "Mr. Navarro. Mr. Kell, who is also called El Chino.

They were cloned at Tycho Station from prehistoric tissue specimens."

"You were cloned for duty there." Lo eyed us severely. "How did you get here?"

"We lied to the ship." Casey straightened wryly to face her. "We did it because we didn't want to live out our lives in that pit on the Moon. I won't say I'm sorry, but now we are in trouble. I don't want to die."

"You will die," she told him bluntly. "Like all your kind. You carry no nanorobs."

"I guess." He shrugged. "But first we want a chance to live."

"Mother, please!" Tling caught her hand. "With no nanorobs, they are in immediate danger here. Can we help them stay alive?"

"That depends on your father."

"I tried to ask him," Tling said. "He didn't answer."

We watched Lo's solemn frown, saw Tling's deepening trouble.

"I wish you had nanorobs." She turned at last to translate for us. "My father has gone out to meet an interstellar ship that has just come back after eight hundred years away. The officers are telling him a very strange story."

She looked up at her mother, as if listening.

"It carried colonists for the planets of the star Enthel, which is four hundred light-years toward the galactic core. They had taken off with no warning of trouble. The destination planet had been surveyedand opened for settlement. It had rich natural resources, with no native life to be protected. Navigation algorithms for the flight had been tested, occupation priorities secured."

She stared up at the sky, in baffled dismay.

"Now the ship has returned, two thousand colonists still aboard."

Casey asked what had gone wrong. We waited, watching their anxious frowns.

"My father is inquiring." Tling turned back to us. "He's afraid of something dreadful."

"It must have been dreadful," Pepe whispered. "Imagine eight hundred years on a ship in s.p.a.ce!"

"Only instants for them." Tling shook her head, smiling at him. "Time stops, remember, at the speed of light. By their own time, they left only yesterday. Yet their situation is still hard enough. Their friends are scattered away. Their whole world is gone. They feel lost and desperate."

She turned to her mother. "Why couldn't they land?"

Her mother listened again. Far out across the valley I saw a little herd of zebras running. I couldn't see what had frightened them.

"My father is asking," she told us at last. "The pa.s.sengers were not told why the ship had to turn back.

The officers have promised a statement, but my father says they can't agree on what to say. They aren't sure what they found on the destination planet. He believes they're afraid to say what they believe."

The running zebras veered aside. I saw the tawny flash of a lion charging to meet them, saw a limping zebra go down. My own ankle was aching from a stone that had turned under my foot, and I felt as helpless as the zebra.

"Don't worry, Mr. Dunk." Tling reached to touch my arm. "My father is very busy with the ship. I don't know what he can do with you, but I don't want the animals to kill you. I think we can keep you safe till he comes home. Can't we, mother?"

Her lips pressed tight, Lo shrugged as if she had forgotten us.

"Please, mother. I know they are primitives, but they would never harm me. I can understand them the way I understand the animals. They are hungry and afraid, with nowhere else to go."

Lo stood motionless for a moment, frowning at us.

"Get in."

She beckoned us into the flyer and lifted her face again as if listening to the sky.

We soared toward a rocky hill and landed on a level ledge near the summit. Climbing out, we looked down across the gra.s.sy valley and over the ridge to Sandor's memorial just beyond. Closer than I expected, I found the bright metal glint of the rebuilt s.p.a.ceplane on the mall, the Capitol dome and the Washington obelisk, the white marble sheen of the Egyptian pyramid looming out of green forest beyond.

"My father picked this spot." Tling nodded toward the cliff. "He wanted to watch the memorial built."

While her mother stood listening intently at the sky, Tling inspected our mudstained safari suits."You need a bath," she decided, "before you eat."

Running ahead, she took us down an arched tunnel into the hill and showed me into a room far larger than my cell below the station dome. Warm water sprayed me when I stepped into the shower, warm air dried me. A human-shaped robot handed me my clothing when I came out, clean and neatly folded. It guided me to a room where Tling was already sitting with Pepe and Casey at a table set with plates around a pyramid of fragrant fruit.

"Mr. Chino asked about my mother." She looked up to smile at me. "You saw that she's different, with different nanorobs. She comes from the Garenkrake system, three hundred light-years away. Its people had forgotten where they came from. She wanted to know. When her search for the mother planet brought her here, she found my father already digging at the Tycho site. They've worked together ever since."

Pepe and Casey were already eating. Casey turned to Tling, who was nibbling delicately at something that looked like a huge purple orchid.

"What do you think will happen to us?"