I stare blankly at her.

“I guess that’s how she could keep tabs on me.” She shrugs. “And how she got me to San Francisco too.”

I smile and nod. I think Grace often has thoughts that make sense in her head but come out incomplete when she tries to convey them. I understand her general meaning, however, and it’s easier to agree than to ask for clarification.

Relaxing into the wrought-iron-and-wicker chair, I scan the street for signs of either Gretchen or Sthenno. Union Square is not my favorite part of town—it’s dirty and crowded and always gives me an unsettled vibe. Tourists love it, though, and the shopping is first-rate.

“Oh look!” Grace shouts. “There’s Gretchen.” She jumps to her feet and starts waving her arms. “Gretchen! Over here!”

Her face blossoms into an even bigger smile, and I assume that Gretchen has seen us and is heading this way. I continue my relaxed survey of the street while Grace pulls over a chair for Gretchen.

I notice a woman walking up the sidewalk on the other side, about two blocks away. She is tall and poised and elegant, and although I can’t seem to place her anywhere, she feels intimately familiar. I can’t look away as she weaves through the crowds effortlessly, almost as if they part before her.

Gretchen drops into the chair next to me. “What are you gawking at?”

I shake my head, unable to lose the sensation that I know this woman from somewhere. I usually trust my brain over my instinct, but the feeling is so overwhelming I can’t simply dismiss it.

Grace twists in her seat to get a look.

“Oh,” she exclaims. “That’s Ms. West. I mean Sthenno.”

Our ancient immortal ancestor?

At that moment, the woman—Ms. West—Sthenno—crosses the street, and a memory flashes into my thoughts. It’s been years. More than a decade. The moment plays in my mind with perfect clarity.

When I was a child, I saw a centaur in my bedroom. It was the only time before my sisterly reunion that I saw a mythological monster, and I eventually came to believe that the vision was a nightmare. A hallucination. Mother started taking me to regular hypnotherapy sessions immediately. The therapist was a middle-aged woman with dark hair that was fading into gray. Then, at one session—the very last—there was a different therapist. She was younger, blonder, and far more effective. One session with her and Mother declared me cured.

I recognize the woman stepping on the sidewalk at the end of the block because she was that final therapist.

A million confused questions flood my brain.

“I—”

Before I can say that I’ve met Sthenno before, a black spot appears next to her in the middle of the air. The spot grows quickly, expanding into a giant hole about the size of a double door.

“What the heck?” Grace blurts.

Gretchen bursts to her feet.

Grace and I sit there, stunned, but Gretchen takes off running. On instinct, I follow. Gretchen is still several feet away from Sthenno when a creature steps out of the hole. It almost looks human—well, it’s human shaped anyway, like a gnarled old woman. She has pale green skin, stark white hair, and blood dripping down her cheeks.

“Achlys!” Gretchen shouts.

The green hag glances our way, startled, as if she didn’t expect anyone to see her.

Then, without hesitation, she wraps both arms around Sthenno and throws her into the hole. Gretchen lunges, barely missing the hag, who follows Sthenno into the blackness. The hole snaps shut just as Gretchen reaches the spot.

She shouts into the empty air. “No!”

“What just happened?” I ask, skidding to a stop next to Gretchen.

Grace catches up, eyes wide. “Where did she go?”

Gretchen glares at the empty spot where the black hole was, then turns and levels a silver glare at each of us. “That was a window into the abyss,” she says. “Sthenno is now their prisoner.”

She looks like she wants to punch something. Anything.

I step back.

“What was that thing?” I ask. “It wasn’t human.”

“No,” Gretchen replies, jamming her hands onto her hips. “Definitely not human. She’s a dark spirit. The demon of misery. I tangled with her once.” Gretchen holds up her forearm, revealing a set of four long, parallel scars. “Her nasty fingernails are tipped with an antihealing poison. Took forever for my wounds to heal.”

“We have to go get her,” Grace says.

My heart trips a little at the idea. Willingly walking into that … blackness? It’s a crazy idea. But as crazy and scary as it is, we don’t have many options. We need answers and Sthenno has them. We need her.

“We do,” I agree. “How?”

Gretchen’s eyes narrow.

“Sure,” she snaps. “It’s just that easy. We’ll go in after her.”

I can do without the sarcasm. “And why not?”

“Is that even possible?” Grace asks.

“It must be,” I insist. “Right?”

“In case you haven’t noticed,” Gretchen says, “the portal is gone.”

She waves her hands in the air, in the space that moments ago was a big black void that led into the abyss. Like we need a lesson in visual reality.

I did not get to be junior class president, alumnae tea cochair, and Women in Business liaison by allowing fears and negative thinking to dictate my actions. I am a firm believer in the adage that where there’s a will, there’s a way.