She picked up a small latch-key from the desk.
"This is number 11, isn't it?" she asked quickly.
"No! Number 11 is the flat immediately overhead," he told her.
She appeared unconvinced.
"But I opened the door with this key," she declared.
"Mr. Barnes and I have similar locks," he said. "The fact remains that this is number 9, and number 11 is one story overhead."
She drew a long breath, presumably of relief, and moved a step forward.
"I am very sorry!" she declared. "I have made a mistake. You must please accept my apologies."
He stood motionless in front of the door. He was pale, clean-shaven, and slim, and in his correct evening clothes he seemed a somewhat ordinary type of the well-bred young Englishman. But his eyes were grey, and his mouth straight and firm.
She came to a standstill. Her eyes seemed to be questioning him. She scarcely understood his attitude.