"Didn't you say that she and I look a bit alike?"
"Only in height and build and fair-headedness and general beauty and all that sort of thing," replied Simon. "You're both the same type, that's all."
"Then leave it to me," said Patricia calmly. "I'll show you what a real detective can do."
It was the conventional tea hour when she entered the handsome new apartment house in the neighbourhood of Marble Arch known as Parkside Court. Number 21 was on the sixth floor, and Patricia went up in the elevator in spite of the fact that the porter had warned her that Miss Avery had given instructions that she was not at home to anybody. The porter had put it more broadly than this; he had declared that Miss Avery had gone down to Cornwall for a holiday — or up into Aberdeenshire, he wasn't sure which. But Patricia had looked at him with her sapphire-blue eyes, so remarkably like the Saint's, and her bewitching smile, and the unfortunate man had dried completely up.
In the carpeted corridor, outside the door of number 21 a man was repairing a vacuum cleaner. Patricia was sorry for him. He had taken the vacuum cleaner apart into so many pieces that it was very doubtful whether it could ever be put together again. Notwithstanding his workmanlike overalls, Patricia had no difficulty in recognizing him as an employee of some private detective agency. He had "ex-policeman" stamped all over him in embossed lettering.
"No good you ringing that bell, miss," he said gruffly as Patricia placed her finger on the button. "There's nobody at home. Miss Avery's gone into the country."
He had looked at her very hard at first with a somewhat startled expression on his face. Patricia knew why. She went on smiling at him.
"Is there any special way of ringing?" she enquired sweetly. "I don't think she'll refuse to see her own sister."
The man suddenly grinned.
"Well, of course that's different, miss," he said hastily. "I thought there was a likeness. Why, when you came round the corner I took you for Miss Avery herself."