Cyrene swore and slammed on the brakes, jerking the car onto a thankfully empty sidewalk, her eyes huge.

I stared down in astonishment at the source of the unseen but still tangible ethereal glow.

‘‘What the—what is that? Gracious goddess, it’s . . . it’s . . .’’

‘‘It’s quintessence,’’ I said, breathing heavily as I allowed the glittering brilliance to sink deep into my bones.

‘‘The what now?’’

‘‘Quintessence. The fifth element.’’

Slowly, I closed the lid of the box, the light ending with an abruptness that left my soul weeping.

‘‘Like the movie, you mean? With Bruce Willis?’’

‘‘What?’’ It took a moment for her words to penetrate the fog that seemed to settle over me with the loss of the light. ‘‘No, not that. That’s just Hollywood. The fifth element is something alchemists strive to find. It’s the essential presence.’’

‘‘Essential presence of what?’’ she asked, carefully pulling back onto the road, but quickly pulling over again when police cars burst out of a cross street, sirens wailing and lights flashing.

‘‘Everything. It’s the above and below. The embodiment of that force we call life. It’s the purest essence of . . . being.’’

‘‘Is it valuable?’’ Cyrene asked, a calculating expression stealing across her face.

My fingers tightened around the box. ‘‘Priceless. Beyond priceless. Invaluable. Any alchemist would kill to have it.’’

‘‘Hmm.’’

I knew what she was thinking. Cyrene had expensive tastes, and no practical ability to save money. I was sure she was going to suggest putting the quintessence up for bid, but that was something I couldn’t allow. ‘‘No,’’ I said.

Her lips, recently plumped and now shaded a delicate pink, pouted in a manner that I knew made grown men swoon. ‘‘Why not? I bet we could get a lot for it.’’

‘‘For one, it’s not mine.’’ I stroked the bumpy crystal lid with worshipful fingers.

‘‘Well, I know Magoth will want it, but that’s not what he sent you there to get, right? So he doesn’t need to know we have it.’’

I shook my head. ‘‘If Magoth thinks I was even near a quintessence . . . well, the phrase ‘hell hath no fury like a demon lord denied’ charges immediately to mind. I can’t begin to describe the horrible things he’d do to me to get it. And to you, for that matter.’’

She shot me a quick glance as we drove through the city to the commercial center, where our hotel was located. ‘‘Me? A demon lord can’t do anything to me. I’m immortal!’’

‘‘So am I, and he could snuff me out as easily as a candle flame.’’

‘‘I can’t believe you never learned this, but demon lords can’t kill elemental beings, naiads included,’’ she said with gentle chastisement. ‘‘Everyone knows that.’’

‘‘So the lore goes, but do you seriously doubt you could escape Magoth’s wrath?’’

‘‘Er . . .’’ She thought about it for a moment, her lips thinning. ‘‘No.’’