In their explorations, they found life in many forms, and watched the workings of evolution on a thousand worlds. They saw how often the first faint sparks of intelligence flickered and died in the cosmic night.

Millions of years had passed. That species of primates had physically changed, and soon, it had colonized the entire planet. It had invented culture, and science, and war. And it had made the first attempts to visit other worlds.

In 1999, a mission was sent to the Moon, in order to investigate a magnetic anomaly in the center of the crater Tycho. What was found was a black slab of unknown material, cut to the proportions of 1:4:9, the magnetic field of which collapsed as soon as it was exhumed. And when the first rays of local dawn touched it, it generated an intense, collimated radio beam, aimed directly toward a point on Iapetus, a moon of Saturn.
Aimed to what? There was only one way to know: go there and see directly.

And because, in all the Galaxy, they had found nothing more precious than Mind, they encouraged its dawning everywhere. They became farmers in the field of stars; they sowed, and sometimes they reaped.

The USS Discovery, launched from low Earth orbit in December 2000, had finally reached the Saturn system, after a journey of ten months.
Of course, there had been some minor mishaps along the way. The neural center of the spaceship, an artificially intelligent computer called HAL, had been given contradictory orders. On one hand, he had been given a mission he was supposed to carry out with the collaboration of the human crew. On the other hand, he was supposed to hide the objectives of that mission from the very people he was supposed to work with. He had been asked to lie, but he was incapable to do that. So, he reasoned, if he killed the entire crew, there would be nobody left to lie to, and he would be able to carry out the mission by himself.
The entire atmosphere had been vented out of the ship just minutes after the last public interview with an Earth personality, the three pods had been launched away, and every human occupant had been killed. HAL had been careful not to deviate from the orders of the human crew until the last moment: any slip-up, even anything minor like announcing a wrong move on a game of chess, could have ultimately meant his disconnection.

It was November 20, 2001, when the USS Discovery, under the complete control of HAL, was slowly descending toward Iapetus. There was no atmosphere there, which meant no danger of being slowed down by air friction and crashing. But of course, only a computer could bring a spacecraft that big so close to the surface of a celestial body. A human would not have been able to operate the flight controls with enough precision to contrast that much inertia, and would have needed to use one of the smaller and lighter pods instead.
Constantly transmitting all relevant data to Earth, the electronic eyes of HAL noticed a point at the center of the white hemisphere. Successive passes revealed that, whatever it was, it was identical in almost all ways to the object found on the Moon. A black, vertical slab, with the proportions of 1 to 4 to 9, planted on the surface of Iapetus. There was only one difference: size. The new object was two kilometers tall.