alarm her. That is certain. The general
sequence of events is pretty clear, is it not? A couple seek refuge in
London from a very terrible and instant danger. The measure of that
danger is the rigour of their precautions. The man, who has some work
which he must do, desires to leave the woman in absolute safety while
he does it. It is not an easy problem, but he solved it in an original
fashion, and so effectively that her presence was not even known to the
landlady who supplies her with food. The printed messages, as is now
evident, were to prevent her sex being discovered by her writing. The
man cannot come near the woman, or he will guide their enemies to her.
Since he cannot communicate with her direct, he has recourse to the
agony column of a paper. So far all is clear."

"But what is at the root of it?"

"Ah, yes, Watson--severely practical, as usual! What is at the root of
it all? Mrs. Warren's whimsical problem enlarges somewhat and assumes
a more sinister aspect as we proceed. This much we can say: that it
is no ordinary love escapade. You saw the woman's face at the sign of
danger. We have heard, too, of the attack upon the landlord, which was
undoubtedly meant for the lodger. These alarms, and the desperate need
for secrecy, argue that the matter is one of life or death. The attack
upon Mr. Warren further shows that the enemy, whoever they are, are
themselves not aware of the substitution of the female lodger for the
male. It is very curious and complex, Watson."

"Why should you go further in it? What have you to gain from it?"

"What, indeed? It is art for art's sake, Watson. I suppose when you
doctored you found yourself studying cases without thought of a fee?"

"For my education, Holmes."

"Education never ends, Watson. It is a series of lessons with the
greatest for the last. This is an instructive case. There is neither
money nor credit in it, and yet one would wish to tidy it up. When
dusk comes we should find ourselves one stage advanced in our
investigation."

When we returned to Mrs. Warren's rooms, the gloom of a London winter
evening had thickened into one gray curtain, a dead monotone of colour,
broken only by the sharp yellow squares of the windows and the blurred
haloes of the gas-lamps. As we peered from the darkened sitting-room
of the lodging-house, one more dim light glimmered high up through the
obscurity.

"Someone is moving in that room," said Holmes in