On the door to the hall, still fastened as the Bat had left it, was the pathetic little creature with which the Bat had signed a job--for once, before he had completed it.
But calmly and dispassionately Miss Cornelia worked out the crossword puzzle of the evening and announced her results.
"It is all clear," she said.

"Of course the Doctor had the blue-print.
And the Bat tried to get it from him.

Then when the Doctor had stunned him and locked him in the billiard room, the Bat still had the key and unlocked his own handcuffs.

After that he had only to get out of a window and shut us in here." And again: "He had probably trailed the real detective all the way from town and attacked him where Mr.Beresford found the watch." Once, too, she harkened back to the anonymous letters-- "It must have been a blow to the Doctor and Courtleigh Fleming when they found me settled in the house!" She smiled grimly.

"And when their letters failed to dislodge me." But it was the Bat who held her interest; his daring assumption of the detective's identity, his searching of the house ostensibly for their safety but in reality for the treasure, and that one moment of irresolution when he did not shoot the Doctor at the top of the ladder.
And thereafter lost his chance-- It somehow weakened her terrified admiration for him, but she had nothing but acclaim for the escape he had made from the Hidden Room itself.
"That took brains," she said.