My fingers brush her neck, finding the pressure point that would end her in seconds. Not yet. First, I need answers.

"Where is she?"

"Who?"

"If you've hurt her..." The words catch in my throat. The thought of my Aileen in pain, scared, alone - it tears at my hearts like razor wire.

Not-Aileen's skin ripples, a flash of green scales showing through. "I don't know what you mean."

The limo slows, gravel crunching under the tires. We've reached the construction site. Good. No witnesses, no interruptions.

"We'll see about that." I check the restraints one final time. "And pray to your goddess you're telling the truth. Because if anything's happened to my Aileen, there won't be enough of you left to fill a specimen jar."

Marcus guns the engine and peels away, leaving us alone in this concrete wasteland. Gravel crunches under my feet as I circle to the passenger door.

"Where is the real Aileen? I'm only going to ask nicely once."

"But I am the real Aileen!" Her voice quavers perfectly. "Baby, you're scaring me."

My hand shoots out, grabs her hair, and slams her face-first through the window. Glass shatters in a crystalline spray. The imposter writhes, whimpering in pain.

"Please..." She uses Aileen's voice, the one that makes my hearts ache. "You're hurting me. Why are you doing this?"

For a heartbeat, doubt creeps in. What if I'm wrong? What if this really is my Aileen?

Then I see it - her skin ripples, turning cerulean blue for just a split second before shifting back to Aileen's olive complexion. The sight makes my blood boil.

"I'm not going to fall for your tricks." My knuckles crack as I flex my fingers. "Tell me where the real Aileen is, or you will regret being alive."

The ropes fall away like water through a sieve. Not-Aileen's body twists impossibly, bones and joints bending in ways that make my stomach turn.

"You can't tie up a shapeshifter, you imbecile." Her skin ripples blue, hair blazing orange. She lunges at me with inhuman speed.

I dodge the first strike but her arm stretches like taffy, wrapping around my throat. My fist connects with her jaw - it's like punching wet clay. The impact leaves a crater in her face that fills back in instantly.

"Aileen. Faker. Aileen. Faker." The words spill from her mouth in a monotone loop, her voice distorting with each repetition.

I slam her against the wall but she flows around me like quicksilver. My claws tear through her flesh but the wounds seal instantly. She reforms behind me, that haunting chant growing louder.

"Aileen. Faker. Aileen. Faker."

Her fingers elongate into tentacles, wrapping around my arms and legs. I rip free only to have her body surge forward like a tidal wave. We crash through a half-finished wall in a shower of drywall and splinters.

"AILEEN. FAKER. AILEEN. FAKER."

The chant echoes off concrete walls as we grapple. Every blow I land just gets absorbed into her malleable form. She's everywhere at once - flowing, shifting, reforming. My training never covered anything like this.

Her face splits into a grotesque grin that stretches ear to ear. "AILEEN FAKER AILEEN FAKER AILEEN FAKER!"

I back away from her flailing limbs, leading her toward the steel skeleton of the unfinished building. The scaffolding rises like a metal mountain against the night sky.

"Come get me, you shape-stealing zealot."

Her body twists and flows as she pursues me up the girders. Each step takes us higher above Chicago's glittering streets. Wind whips at my clothes, the city spreading out beneath us like a carpet of stars.

"AILEEN FAKER AILEEN FAKER!"

Perfect. The thing's so focused on its prey, it doesn't notice the trap. We reach the highest platform, nothing but empty air between us and the ground far below.