Ever since 1969, when America's Apollo 11 carried men to the surface of the moon—Armstrong and Aldrin taking one small step, and civilization a giant leap—the United States had gone on to launch six more Apollo missions; save for one that exploded, the other five all landed on the moon.

The last was in 1972.

After that came no more crewed lunar missions. Past the turn of the twenty-first century, the American and Russian space programs had both gone slack, and only China's kept climbing.

Yet though China had launched the International Space Station, it had only reached the "return" stage of its three-stage orbit–land–return program, bringing back a batch of lunar rock samples; a crewed landing had not yet begun.

And then the end of the world arrived.

"I don't believe the Americans ever landed on the moon!" Shen Cong was a believer in conspiracy theories, forever convinced that America had deliberately staged the whole moon landing—and there were plenty of threads that seemed to bear him out.

There had been no landings in the decades since, for one. The moon rock given to the Netherlands had turned out to be fake. The landing crew were barred from interviews. And on and on.

None of which, of course, had anything to do with the radiative fluctuation Shen Cong was picking up now.

He quietly analyzed the fluctuation his waves had suddenly snagged, sifting the information it carried—it held a complex, orderly structure, the rhythm of its particle vibration nothing spontaneous but emitted on purpose, and some of its structures bore an unmistakably man-made stamp.

"There's life on the moon—higher intelligent life, even?"

Shen Cong couldn't work out what this repeating, orderly fluctuation actually meant, but his face had turned somewhat grave.

He might often lull himself with the thought that his future lay in the sea of stars, that he'd break free of Earth and strike out into the cosmos, into distant interstellar space to hunt down the source of evolution. But in his heart Shen Cong knew leaving Earth was no simple matter—it might not be possible in…