“Listen, Bill,” they continued. “Our scientists have just discovered that your sun is about to explode. It will happen three days from now—seventy-four hours, to be exact. Nothing can stop it. But there’s no need to be alarmed. We can save you, if you’ll do what we say.”

“Go on,” said Bill. This hallucination was ingenious.

“We can create what we call a bridge—it’s a kind of tunnel through space, like the one you’re looking into now. The theory is far too complicated to explain, even to one of your mathematicians.”

“Hold on a minute!” protested Bill. “I am a mathematician, and a darn good one, even when I’m sober. And I’ve read all about this kind of thing in the science-fiction magazines. I presume you’re talking about some kind of short cut through a higher dimension of space. That’s old stuff—pre-Einstein.”

A sensation of distinct surprise seeped into Bill’s mind.

“We had no idea you were so advanced scientifically,” said the Thaarns. “But we haven’t time to talk about the theory. All that matters is this—if you were to step into that opening in front of you, you’d find yourself instantly on another planet. It’s a short cut, as you said—in this case through the thirty-seventh dimension.”

“And it leads to your world?”

“Oh no—you couldn’t live here. But there are plenty of planets like Earth in the universe, and we’ve found one that will suit you. We’ll establish bridgeheads like this all over Earth, so your people will only have to walk through them to be saved. Of course, they’ll have to start building up civilization again when they reach their new homes, but it’s their only hope. You have to pass on this message, and tell them what to do.”