“Sshh! Sssh!” I hiss up at her, but she is sixty feet above me, she cannot hear. Mary’s cold hand slips into mine. Ruth isn’t moving, the porter is not letting her down, something has gone terribly wrong, then she falls like a bag of dusters, the rope snaking down from above her as he drops it, and we hear her terrified scream.

The thud when she hits the ground is an awful sound. She has broken her back, for sure. I run to her side at once, and she is moaning in pain, her hand clamped over her mouth, trying, even at this moment, not to betray me.

“Your Grace!” Mary Seton is tugging at my arm. “Run! They are coming.”

I hesitate for a moment; Ruth’s pale face is twisted with agony; now she has her fist thrust in her mouth, trying not to cry out. I look towards the main gate. The sentries, having heard her scream, are turned questingly towards the castle; a man runs forward, shouts to another; someone brings a torch from the sconce at the gateway. They are like hounds spreading out to scent the quarry.

I pull my hood up over my head to hide my face and start to duck backwards into the shadows. Perhaps we can get around the castle and out of a back gate. Perhaps there is a sallyport or somewhere we can hide. Then there is a shout from inside the castle: they have raised the alarm in my chambers. At once the night is ablaze with the bobbing flames of torches and “Hi! Hi! Hi!” they bellow like hunters, like beaters driving the game before them.

I turn to one side and then the other, my heart thudding, ready to run. But now they have seen us silhouetted by their torches against the dark walls of the castle, and there is a great bellow of “View halloa! Here she is! Cut her off! Run round! Here she is! Bring her to bay!”