and a
guest vouched for (especially at five and threepence) by an Arkwright
was a person to be considered.

This at a price, and a curious price at that. "In some things I am a
faddist," Miss Arkwright had said the morning after his arrival. "I
admit it freely. I am glad to welcome you here, Mr. Mortimer, but if you
stay you must give me your word not to go outside my grounds during your
visit. The garden is large--the village uninteresting, so your curtailed
liberty will not be much of a deprivation. You think me insane, perhaps?
Well, I have reasons for my wish,--personal reasons into which I can not
enter. That is the only stipulation I make: can you accept it?"

He said yes, for refusal meant a lodging at the inn, where he could not
watch her. In his letter to Beatrice he told her of this extraordinary
whim, and asked whether she thought it better to agree or to pack up and
go. Her "stay at all costs" was sufficient answer, and though he hoped
this did not mean "If need arise, break bounds and your word," still he
meant to do it if necessary. The life of Lukos and her happiness were
worth more than a detective's honor.

But up to the present there had been no question of breaking bounds. He
could see nothing of Mr. "Beckett" nor Mizzi, but he was obeying
Beatrice. And it was not unpleasant even for a detective to enjoy
luxurious idleness, a perfect garden and the society of a charming
woman. For she was charming, despite her fads and bigotry. She was well
read, exceedingly pretty, and could talk. The mornings she spent in
writing and arranging her household affairs. After lunch she gave
herself up to him entirely. Tea they usually had together in the
summer-house. About five she always excused herself, and Lionel dined
alone. He was given to understand that she was busy on a history of the
Arkwright family and could work best at night. Consequently he never saw
anything of her again till breakfast.

This naturally struck him as one of the most suspicious features of the
case. Suspicious--not in the sense that Miss Arkwright was an Ottoman
conspirator, for that he had been instructed to expect; but suspicious
for a deeper reason. More than once during the first week of his stay he
had caught himself wondering, "Can she be, by any chance, Beatrice
herself, masquerading as her own sister?" It was a solution that
suggested itself to a mind seeking explanation of extraordinary things,
extraordinary people. It was the