"Yes!" said the girl. "I feel sure there is."
"And that shows that there's something very wrong somewhere. Mr. Boyne has, in secret, a guest who is in hiding upstairs. He takes him food and water every night—as we have seen with our own eyes. And, further, he had taken the precaution of installing an electrical alarm in case anyone followed him upstairs while he was there with his friend."
"True," said the girl. "But why does he disguise himself whenever he goes up there?"
"That we cannot yet tell. At present it is a complete mystery."
"And a most uncanny one!"
"It is, I can't see the motive of that disguise."
"Is it not weird? He was covered from head to foot in that white cloak, and only those two slits for his eyes."
"Yes. And he moved as silently as a shadow."
So the pair conversed until they reached the Broadway Station, and left by the Underground a few moments later.
What they had witnessed that night had increased the mystery a hundredfold.