e, if you please. I must
speak to your brother."

"Have you been able to think of anything?" she asked, anxiously. "Is
there any chance at all, do you think?"

"I believe so," Peter Ruff answered. "It is most interesting. Don't
be too sanguine, though. The odds are against us, and the time is very
short. Is the driver of your electric brougham to be trusted?"

"Absolutely," she assured him. "He is an old servant."

"Will you lend him to me?" Peter Ruff asked, "and tell him that he is to
obey my instructions absolutely?"

"Of course," she answered. "You are going away, then?"

Peter Ruff nodded. He was a little sparing of words just then. The
thoughts were chasing one another through his brain. He was listening,
too, for the sweep of a dress behind.

"Is there nothing I can do?" Lady Mary begged, eagerly.

Peter Ruff shook his head. In the distance he saw the Honourable Maurice
come quickly toward them. With a firm but imperceptible gesture he waved
him away.

"Don't let your brother speak to me," he said. "We can't tell who is
behind. What time did you say the Prime Minister was expected?"

"At two o'clock," Lady Mary said, anxiously.

Peter Ruff glanced at his watch. It was already half an hour past
midnight.

"Very well," he said, "I will do what I can. If my theory is wrong, it
will be nothing. If I am right--well, there is a chance, anyhow. In the
meantime--"

"In the meantime?" she repeated, breathlessly.

"Take your brother back to the ballroom," Peter Ruff directed. "Make him
dance--dance yourself. Don't give yourselves away by looking anxious.
When the time is short--say at a quarter to two--he can come down here
and wait for me."

"If you don't come!" she exclaimed.

"Then we shall have lost," Peter Ruff said, calmly. "If you don't see
me again to-night, you had better read the newspapers carefully for the
next few days."

"You are going to do something dangerous!" she protested.

"There is danger in interfering at all in such a matter as this," he
answered, "but you must remember that it is not only my profession--it
is my hobby. Remember, too," he added, with a smile, "that I do not
often lose!"

For twenty minutes Peter Ruff sat in the remote corner of Lady Mary's
electric brougham, drawn up at the other side of the Square, and waited.
At last he pressed a button. They glided off. Before them was a large,
closed motor car. They started in discreet chase.

Fortunately, however, the