"Then listen, Monsieur. First, as to the door of our cell. It is locked with a key, which the Count himself retains, except when he goes out, as this afternoon,—it is then entrusted to the seneschal. I know this from Brigitte, for the key is given to her when she comes to us. She hands it to the guard on the landing, who opens the door and keeps the key while she is within. When she leaves us, he locks the door, and she takes the key back to the Count or seneschal. But in order to release Madame, you must have that key."
"And how am I to get it?"
"After Brigitte's last visit to us before the night we select, she will give the Count or seneschal, not the real key to our cell, but another of the same size and general shape—she has access to unimportant keys about the house. Then she will bring the real key to you."
"But poor Brigitte!—when the Count investigates in the morning, he will find she has given him the wrong key."
Mathilde thought a moment. "No; he will rather suppose you robbed him of the right key during the night and substituted the other to delay discovery. He will suspect anything rather than Brigitte, whom he thinks too great a fool for the least craft; and even if she is accused, she can play the innocent. I assure you."
"So much for that, then. There is yet the door of entrance to the tower."
"At present it has an old broken key in the lock, which is therefore useless. But no doubt that will be remedied—so we must act soon. Meanwhile, that door is guarded by the man at the foot of the stairs."
"But are the two guards on duty at night also? There is no Brigitte to be let in and out then. And surely the Count doesn't think you can break your lock."
"There are guards on duty, nevertheless. Last night I heard one call down the stairs to another, asking the time. They are there, no doubt, not for fear of our breaking out, but for fear of somebody breaking in to help Madame. I don't suppose there are ever more than two. If the rule has not been changed, the rest of the household sleeps, except a porter in the gate-house and a man on top of the tower. But this man watches the roads, as well as he can in the darkness, and the porter too is more concerned about people who might want to enter the chateau than about what goes on inside. So in the dead of night you can go silently downstairs and let yourself out of the hall—"
"But is not the hall door locked with a key?"