speed of an arrow, yet
stopped as gently as though she had merely floated there.

As she looked up, her eyes unmistakably sought mine, and her smile
seemed warm and inviting. She made again that strange little gesture of
invitation.

With an effort I glanced at Mercer. There was something devilishly
fascinating about the girl's great, dark, searching eyes.

"I'm going in," I said hoarsely. "Hand me one of your head-set things
when I reach for it." Before he could protest, I dived into the pool.

* * * * *

I headed directly towards the heavy bronze ladder that led to the bottom
of the pool. I had two reasons in mind. I would need something to keep
me under water, with my lungs full of air, and I could get out quickly
if it were necessary. I had not forgotten the livid, jagged furrows in
Mercer's side.

Quickly as I shot to the ladder she was there before me, a dim, wavering
white shape, waiting.

I paused, holding to a rung of the ladder with one hand. She came
closer, walking with the airy grace I had noted before, and my heart
pounded against my ribs as she raised one long, slim arm towards me.

The hand dropped gently on my shoulder, pressed it as though in token
of friendship. Perhaps, I thought quickly, this was, with her, a sign of
greeting. I lifted my own arm and returned the salutation, if salutation
it were, aware of a strange rising and falling sound, as of a distant
humming, in my ears.

The sound ceased suddenly, on a rising note, as though of inquiry, and
it dawned on me that I had heard the speech of this strange creature.
Before I could think of a course of action, my aching lungs reminded me
of the need of air, and I released my hold on the ladder and let my body
rise to the surface.

* * * * *

As my head broke the water, a hand, cold and strong as steel, closed
around my ankle. I looked down. The girl was watching me, and there was
no smile on her face now.

"All right!" I shouted across the pool to Mercer, who was watching
anxiously. Then, filling my lungs with air again, I pulled myself, by
means of the ladder, to the bottom of the pool. The restraining hand was
removed instantly.

The strange creature thrust her face close to mine as my feet touched
bottom, and for the first time I saw her features distinctly.

She was beautiful, but in a weird, unearthly sort of way. As I had
already noticed, her eyes were of unusual s