You know,” said Port, and his voice sounded unreal, as voices are likely to do after a long pause in an utterly silent spot, “the sky here’s very strange. I often have the sensation when I look at it that it’s a solid thing up there, protecting us from what’s behind.” Kit shuddered slightly as she said: “From what’s behind?” “Yes.” “But what is behind?” Her voice was very small. “Nothing, I suppose. Just darkness. Absolute night