As little as I am, I can still defeat you.” Marie grinned at Thallo. “You may have fooled them into thinking you are perfect, but I know you have weaknesses.” The girl crouched in a fighting stance, which made her look even smaller than she really was. Less threatening and deceptively benign. Like her rival on the grassy playfield, she wore a full-body filmsuit and remained barefoot.

“You look just like a harmless child,” he countered mildly. “But I no longer make the mistake of underestimating you.”

It was early afternoon, a cool day in Thalidei, with trees swaying in a breeze blowing across the polluted lake. Tleilaxu men held onto their weather-hats. Despite the illusion of freedom, Thallo’s trainers and observers were always close by. Two lab technicians watched from opposite sides of the field, dictating notes into lapel imagers that sparkled in sunlight.

In the guarded park, Thallo towered statuesque and confident over Marie. He moved only enough to watch the little girl as she circled him. “You bruised me yesterday,” he said, “but it will not happen again.”

“You enjoyed the bruises.” That time, after Marie had struck his lower legs with hard kicks, Thallo had limped back to the laboratory building, unable to hide the pain. Technicians had rushed to apply fast-healing medical packs on him, but Dr. Ereboam insisted on tending the injuries himself, shooing everyone else out of sight — including Marie — before peeling away the beige filmsuit.

Marie realized the truth: Because the albino researcher knew about Thallo’s propensity for cutting himself and had carefully hidden the fact from his peers, Ereboam couldn’t let anyone see the fresh scabs and old scars. The girl wondered how often the mysterious and insular Tleilaxu lied to each other.

Today, Thallo’s limited range of movement suggested that his legs still hurt. Nevertheless, he lunged unexpectedly, striking out at her with a stiff-fingered hand, but she slipped to one side so that he missed her by centimeters. His blow brushed past her, and she didn’t even feel the breeze.

With her varied and intense training, Marie considered herself more than a match for this maladjusted Tleilaxu creation. Still, she played — and fought — with him, observing carefully, continually learning, and Thallo was learning from her as well. They would be a formidable fighting team.

Using perceptive techniques her mother had taught, Marie had come to understand Thallo. He had exceptional fighting skills and a wealth of encyclopedic knowledge, but the Tleilaxu treated him as a specimen, a valuable experiment, a child. Sometimes he acted the role of child for his own amusement. Spurts of action and game playing were only distractions for him, after which he would often wallow in depression, as if slipping into a dark chasm. He was falling now; she could see it.

She kicked at his shins with her hardened feet. He dodged, moving back defensively. She pursued, kicking again and again, but narrowly missed each time. Despite her best efforts, even when she was certain the blows had landed perfectly, she never managed to touch him.

Thallo taunted her. “You have to do better than that!” His voice didn’t sound quite right; it seemed to come from all directions, as if the breeze scattered it all around her. Was he throwing his voice to distract her?

Marie executed a series of speed-somersaults, spinning past him and then coming around from behind. Finally, just as he turned to face her, she landed with her hands on the grass and launched her tiny body toward him in a proven Bene Gesserit bullet maneuver. She hit the middle of his abdomen — and passed completely through his body, landing in tumbling disarray on the rough lawn.

Thallo laughed at her astonishment “I’m too fast for you!” His lips moved as he spoke, but once more the voice did not seem to come from the right direction. “I am the Kwisatz Haderach. I can do anything.”

Marie brushed herself off, glanced over at the observers, whose expressions showed consternation. “How did you really do that?” she asked in a low voice.

His face remained cool, like a porcelain mask. “Does a magician reveal the secret of his tricks?”

“To his best friend, he would.”

“Friends.” He had a perplexed, troubled expression. Then he whispered, “I can’t tell you here.”

Thallo stood like a statue, exploring his own internal realms. What was he thinking? Was he performing Mentat calculations? His face had gone uncharacteristically blank, and though he stared back toward Marie, he didn’t seem to see her. His expression shifted, as if currents were ebbing and flowing in his psyche. She noticed how quiet the training field had grown. On the other side of the bluish grass, the observers seemed to be holding their breath.

“Follow me.” Abruptly adopting a childlike personality, Thallo shouted, “Hide and seek!” With that, he darted off. As she ran after him, Marie heard the lab technicians trying to keep up, and calling ahead for assistance. She saw a guard spring into action, running toward them from the right.

With his long, muscular legs and athletic ability, Thallo easily outdistanced the guard and the technicians. Marie kept up with him as she ran down a short slope and entered a moss-overgrown tunnel that passed beneath a walking bridge. In the shadows, Thallo ducked to his right and disappeared from view. She hurried after him into another tunnel, but to her surprise she heard him call from behind, “Not that way. Over here — now!”

Confused, she turned and saw him in low light, just inside the entrance of another tunnel. Thalidei was riddled with them, but he couldn’t possibly have moved so swiftly. “How did you get here?”

“More magic.” Then, whispering in her ear, Thallo added, “That was just an enhanced solido holo-image out there. I adapted their technology beyond what even the Tleilaxu think they can do. That’s why you couldn’t touch me. I have been waiting down here all the time.”

A light flickered out in the opposite tunnel as the guards pushed inside, angrily trying find them. They did not guess what Thallo had done to their own systems.

Thallo continued in an excited rush, “I can defeat any security and surveillance system they have. This time I will let them catch me, but only because I’m not ready yet.”

“Not ready for what?”

“We don’t have much time.” He whispered his confession to her. “By being so close to perfection, I can plainly see how far I fall short of the mark. Dr. Ereboam knows I am not the flawless Kwisatz Haderach. As soon as the other Masters realize it, they will terminate the experiment — and Ereboam as well. Then they will try again.”

Their pursuers came at them from different directions in the shadowy tunnels, shouting, shining lights. Looking meek and immature again, Thallo stepped forward and raised his hands in mock surrender.

THAT EVENING, THALLO disabled the security systems around him and used the same trick for Marie, leaving full-spectrum holos of them in their respective beds. Though the girl was uneasy about slipping past her unsuspecting parents, she calculated that it was a wise investment to see what her purported friend had in mind. Information is the best defensive weapon. Before she could confide in her mother and father, she needed to understand Thallo’s game.

On a moonless night, the pair of playmates slipped away into silent and brooding Thalidei. They found a place to sit in the middle of a skeletal, abandoned construction site near the shore of the fetid-smelling lake, and they talked for much of the night. As they gazed back toward the flickering lights of the city, Marie continued her own work of understanding, and perhaps even shaping, the young man’s psyche as her parents had taught her, hoping to shift Thallo’s loyalty to her instead of to the Tleilaxu.

This Kwisatz Haderach candidate had more potential than she’d realized at first. Maybe he really could peer into the murky future as he claimed, and maybe he did know with absolute certainty that he was doomed to failure. But if so, he had a blind spot when it came to Marie, and a glaring weakness that she intended to exploit. Thallo was desperate to escape the clutches of the Tleilaxu, and Marie would help him do exactly that.