sperate 'somebody,' who doesn't stop even at murder. A very
devil incarnate who seems to possess the power of invisibility and who
strikes in the dark. Save me, Mr. Cleek! All I've got in the world is at
stake, and if anything happens to Black Riot, I'm a ruined man."

"Yar-r-r!" yawned the elderly sea captain, rising and stretching. "I do
believe, constable, I've been asleep. Warm weather this for May. A
glorious week for Epsom. Shan't see you to-morrow, I'm afraid. Perhaps
shan't see you until Thursday. Here, take that, my lad, and have
half-a-crown's worth on Black Riot for the Derby; she'll win it, sure."

"Thanky, sir. Good luck to you, sir."

"Same to you, my lad. Good day." Then the old gentleman in the top hat
and gray spats moved slowly away, passed down the tree-shaded walk,
passed the romping children, passed the Princess Louise's statue of
Queen Victoria, and, after a moment, vanished. Ten minutes later, when
Narkom and Sir Henry returned to the waiting motor, they found him
seated within it awaiting them, as he had promised. Giving Lennard
orders to drive about slowly in the least frequented quarters, while
they talked, the superintendent got in with Sir Henry, and opened fire
on the "case" without further delay.

"My dear Cleek," he said, "as you appear to know all about Sir Henry and
his famous mare, there's no need to go into that part of the subject,
so I may as well begin by telling you at once that Sir Henry has come up
to town for the express purpose of getting you to go down to his place
in Suffolk to-night in company with him. You are his only hope of
outwitting a diabolical agency which has set out to get at the horse and
put it out of commission before Derby Day, and in the most mysterious,
the most inscrutable manner ever heard of, my dear chap. Already one
groom who sat up to watch with her has been killed, another hopelessly
paralysed, and to-night Logan, the mare's trainer, is to sit up with her
in the effort to baulk the almost superhuman rascal who is at the bottom
of it all. Conceive, if you can, my dear fellow, a power so crafty, so
diabolical, that it gets into a locked and guarded stable, gets in, my
dear Cleek, despite four men constantly pacing back and forth before
each and every window and door that leads into the place and with a
groom on guard inside, and then gets out again in the same mysterious
manner without having been seen or heard by a living soul. In addition
to all the