Suddenly Babu, the astronomer, laughed out loud and said, “I think I know what it is!” and began calling out orders to his own pad, initiating searches for a curious combination of 1980s musical compositions and press reports on African droughts.

“Got it!” he announced triumphantly. “The Intruders seem to be rebroadcasting what remains to this day the loudest, most highly synchronized electromagnetic shout ever sent out from Earth. On April 5, 1985, as part of a publicity effort to bring aid to the starving children of Africa, every radio and television station on every continent began broadcasting the same message at the same moment— a composition called ‘We Are the World,’ by one Michael Jackson. I’m not trying to sound ironic, but I suspect the Intruders are telling us what first drew their attention to our species.”

“So this Michael Jackson became the first definitive sign of intelligent life on Earth,” Sargenti said acidly. “And the Intruders are throwing it back at us. Whatever for?”

“To mock us?” General Stoff asked. “But of course that can’t be true.”

“So what did they do all these years?” Sargenti said. “Just wait around replaying this tune to themselves until they could build starships and come finish us off? They must be insane!”

“Or very determined music critics,” Isak said.

“It just doesn’t make sense,” the astronomer added.

“No, it’s the only thing that does,” said Bishop. “Most likely, the Jackson piece merely alerted them to our presence. Now … 1985 … that’s roughly forty-five years each way at lightspeed … relativistic bombs came in at ninety-two percent c…. If the Intruders responded immediately with relativistic attack, that would put their launch point, at most, forty light-years away. My guess is that they watched for a while, aimed a lot of detectors at us, and waited to see if we might become a threat to them. Our first antimatter engines began shining gamma rays to the galaxy about 2010. I’d say that marks the moment we signed our death warrant, although the song had already suggested a unified world that might take its first steps into interstellar space at any time. I’d say that the Intruder star is somewhere within thirty lights of us.”

“All that from one song?” returned Sargenti. “It has to be a deception. Has to be. Why would they risk telling us so much about themselves—and actually giving us a maximum possible radius of origin? They’d have to be fools.”

“General Sargenti,” Bishop replied, “there’s no doubt they’re smart. But if you pressed me to compare them sight unseen to some Earthly species, I’d have to say there’s something distinctly feline about them. I don’t know how long we’ll be allowed to go on, but I do understand their behavior. They mean to wear down what’s left of us, like cats waiting outside a mouse hole, and they know they have the strength to do it. We’ve become a game to them.”

He paused, distracted by his pad, which was still playing “We Are the World”; but an odd overlayering of whirrs and squeals seemed to be creeping up from somewhere below. Bishop began scribbling, and volumes of an alien binary code scrolled down his pad. He stopped at random on a “page,” and the figures shifted, as if the Intruder program were reprogramming itself.