Gerard had already sprung from his horse, and was leading him through the bushes.  I followed his example, and in a minute or two we made our way down a winding path into a deep chalk quarry.

‘There is no sign of him!’ cried Gerard.  ‘He has escaped us.’

But suddenly I had understood it all.  His furious rage which the miller had described to us was caused no doubt by his learning how he came to be betrayed upon the night of his arrival.  This sweetheart of his had in some way discovered it, and had let him know.  His promise to deliver himself up to-morrow was in order to give him time to have his revenge upon my uncle.  And now with one idea in his head he had ridden to this chalk quarry.  Of course, it must be the same chalk quarry into which the underground passage of Grosbois opened, and no doubt during his treasonable meetings with my uncle he had learned the secret.  Twice I hit upon the wrong spot, but at the third trial I gained the face of the cliff, made my way between it and the bushes, and found the narrow opening, which was hardly visible in the gathering darkness.  During our search Savary had overtaken us on foot, so now, leaving our horses in the chalk-pit, my two companions followed me through the narrow entrance tunnel, and on into the larger and older passage beyond.  We had no lights, and it was as black as pitch within, so I stumbled forward as best I might, feeling my way by keeping one hand upon the side wall, and tripping occasionally over the stones which were scattered along the path.  It had seemed no very great distance when my uncle had led the way with the light, but now, what with the darkness, and what with the uncertainty and the tension of our feelings, it appeared to be a long journey, and Savary’s deep voice at my elbow growled out questions as to how many more miles we were to travel in this moleheap.

‘Hush!’ whispered Gerard.  ‘I hear someone in front of us.’

We stood listening in breathless silence.  Then far away through the darkness I heard the sound of a door creaking upon its hinges.

‘On, on!’ cried Savary, eagerly.  ’The rascal is there, sure enough.  This time at least we have got him!’

But for my part I had my fears.  I remembered that my uncle had opened the door which led into the castle by some secret catch.  This sound which we had heard seemed to show that Toussac had also known how to open it.  But suppose that he had closed it behind him.  I remembered its size and the iron clampings which bound it together.  It was possible that even at the last moment we might find ourselves face to face with an insuperable obstacle.  On and on we hurried in the dark, and then suddenly I could have raised a shout of joy, for there in the distance was a yellow glimmer of light, only visible in contrast with the black darkness which lay between.  The door was open.  In his mad thirst for vengeance Toussac had never given a thought to the pursuers at his heels.