Only then was Tagiri able to think back to cryptic conversations over breakfast or supper, when her parents had congratulated each other for various accomplishments. Now, no longer naive, Tagiri could remember their words and realize that they had been digging knives into each other's pride. And so it was that at the cusp of her childhood, she suddenly reexperienced all of her life till then, only in reverse, with the result clear in her mind, thinking backward and backward, discovering the true causes of everything. That was how she had seen life ever since -- long before she thought of using her university study in ethnology and ancient languages as an entree to Pastwatch.

They did not ask her why her timeflow ran backward, and she did not tell them. Though she was vaguely uneasy that she had not yet been assigned to anything, Tagiri was also glad, for she was playing the greatest game of her life, solving puzzle after puzzle. Hadn't Amami's daughter been late to marry? And hadn't her daughter in turn married too young, and to a man who was far more strong-willed and selfish than her mother's kind but compliant husband? Each generation rejected the choices of the generation before, never understanding the reasons behind the mother's life. Happiness for this generation, misery for the next, but all traceable back to a rape and an unjust beating of an already miserable woman. Tagiri had heard all the reverberations before at last she came upon the ringing bell; she had felt all the waves before she came, at last, to the stone dropping into the pool. Just as it had been in her own childhood.

By all signs, she would have a strange and intriguing career, and her personnel file was given the rare status of a silver tag, which told anyone who had authority to reassign her that she was to be left alone or encouraged to go on with whatever she was doing.

In the meantime, unknown to her, a monitor would be permanently assigned to her, to track all her work, so that in case (as sometimes happened with these strange ones) she never published, upon her death a report on her life's work would be issued anyway, for whatever value it might then have. Only five other people had silver tags on their files when Tagiri achieved this status. And Tagiri was the strangest of them all.

Her life might have gone on that way, for nothing outside her was allowed to interfere with the course she naturally followed. But well into her second year of personal research, she came upon an event in the village of Ikoto that turned her away from one path and into another, with consequences that would change the world. She was backtracking through the life of a woman named Diko. More than any other woman she had studied, Diko had won Tagiri's heart, for there was from the day of her death on back an air of sadness to her that made her seem a figure of tragedy. The others around her sensed it, too -- she was treated with great reverence, and often was asked for advice, even by men, though she was not one of the omen-women and performed no more priestly rites than any other Dongotona.

The sadness remained, year before year, back and back into her years as a young wife, until at last it gave way to something else: fear, rage, even weeping. I am close, thought Tagiri. I will find out the pain at the root of her sadness. Was this, too, some act of her husband's? That would be hard to believe, for unlike Amami's husband, Diko's was a mild and kind man, who enjoyed his wife's position of respect in the village while never seeming to seek any honor for himself. Not a proud man, or a brutal one. And they seemed, in their most private moments, to be genuinely in love; whatever caused Diko's sadness, her husband was a comfort to her.

Then Diko's fear and rage gave way to fear alone, and now the whole village was turned out, searching, hunting through the brush and the forest and along the riverbanks for something lost. Someone lost, rather, for there were no possessions among the Dongotona that would be worth searching for so intently, if lost -- only human beings had such value, for only they were irreplaceable.

And then, suddenly, the search was unbegun, and for the first time Tagiri could see the Diko that might have been: smiling, laughing, singing, her face fined with perfect delight at the life the gods had given her. For there in Diko's house Tagiri now saw for the first time the one whose loss had brought Diko such deep sadness all her life: an eight-year-old boy, bright and alert and happy. She called him Acho, and she talked to him constantly, for he was her companion in work and play. Tagiri had seen good mothers and bad in her passage through the generations, but never such a delight of a mother in her son, and of a son in his mother. The boy also loved his father, and was learning all the manly things from him as he should, but Diko's husband was not as verbal as his wife and firstborn son, so he watched and listened and enjoyed them together, only occasionally joining in their banter.

Perhaps because Tagiri had watched with such suspense through so many weeks, searching for the cause of Diko's sadness, or perhaps because she had come to admire and love Diko so much during her long passage with her, Tagiri could not do as she had done before, and simply continue to move backward, to Acho's emergence from Diko's womb, back to Diko's childhood home and her own birth. Acho's disappearance had had too many reverberations, not just in his mother's life but, through her, in the lives of the whole village, for Tagiri to leave the mystery of his disappearance unsolved. Diko never knew what happened to her boy, but Tagiri had the means to find out. And besides, even though it meant changing direction and searching forward in time for a while, tracking, not a woman, but a boy, it was still a part of her backward search. She would find what it was that took Acho and caused Diko's endless grief.

There were hippos in the waters of the Koss in those days, though rarely this far upriver, and Tagiri dreaded seeing what the villagers assumed -- poor Acho broken and drowned in the jaws of a surly hippopotamus.

But it was not a hippo. It was a man.

A strange man, who spoke a language unlike any that Acho had heard -- though Tagiri recognized it at once as Arabic. The man's light skin and beard, his robe and turban, all were intriguing to the nearly naked Acho, who had seen only people with dark brown skin, except when a group of blue-black Dinkas came hunting up the river. How was such a creature as this possible? Unlike other children, Acho was not one to turn and flee, and so when the man smiled and talked his incomprehensible babble (Tagiri knew he was saying, "Come here, little boy, I won't hurt you") Acho stood his ground, and even smiled.

Then the man lashed out with his stick and knocked Acho senseless to the ground. For a moment the man seemed concerned that he might have killed the boy, and he was satisfied to find Acho was still breathing. Then the Arab folded the unconscious child into fetal position and jammed his small body into a bag, which he hoisted over his shoulder and carried back down the riverbank, where he joined two other companions, who also had full bags.

A slaver, Tagiri realized at once. She had thought they did not come this far. Usually they bought their slaves from Dinkas down at the White Nile, and the Dinka slavers knew better than to come into the mountains in groups so small. Their method was to raid a village, kill all the men, and take the small children and the pretty women off for sale, leaving only the old women behind to keen for them. Most of the Muslim slavers preferred to trade for slaves rather than to do their own kidnapping. These men had broken with the pattern. In the old marketeering societies that nearly ruined the world, thought Tagiri, these men would have been viewed as vigorous, innovative entrepreneurs, trying to make a bit more profit by cutting out the Dinka middlemen.