ironically.

"There is no key. You know it."

"I mean the code book."

"I would like to try to find it."

"How are you going to go about it?"

"I don't know yet."

Vaux smiled. "All right; go ahead, my dear Miss Erith. You're
officially detailed for this delightful job. Do it your own way, but
do it--"

"Thank you so much!"

"--In twenty-four hours," he added grimly. "Otherwise I'll turn it
over to the P.I."

"Oh! That IS brutal of you!"

"Sorry. But if you can't get the code-book in twenty-four hours I'll
have to call in the Service that can."

The girl bit her lip and held out her hand for the letter.

"I can't let it go out of my office," he remarked. "You know that,
Miss Erith."