The children and their companions were clinging to what was not even a ledge – just some lucky hand and footholds – on the edge of that abyss, and there was no way out except forwards, along the slope, among the shattered rocks and the teetering boulders which, it seemed, the slightest touch would send hurtling down below.

And behind them, as the dust cleared, more and more of the ghosts were gazing in horror at the abyss. They were crouching on the slope, too frightened to move. Only the harpies were unafraid; they took to their wings and soared above, scanning backwards and forwards, flying back to reassure those still in the tunnel, flying ahead to search for the way out.

Lyra checked: at least the alethiometer was safe. Suppressing fear, she looked around, found Roger’s little face, and said:

“Come now, we’re all still here, we en’t been hurt. And we can see now, at least. So just keep going, just keep on moving. We can’t go any other way than round the edge of this…” she gestured at the abyss. “So we just got to keep going ahead. I swear Will and me’ll just keep on till we do. So don’t be scared, don’t give up, don’t lag behind. Tell the others. I can’t look back all the time because I got to watch where I’m going, so I got to trust you to come on steady after us, all right?

The little ghost nodded. And so, in shocked silence, the column of the dead began their journey along the edge of the abyss. How long it took, neither Lyra nor Will could guess; how fearful and dangerous it was, they were never able to forget.

Philip Pullman, His Dark Materials, The Amber Spyglass