Disclaimer: I don't own Supergirl or any of the characters from the show or the comic!

Set up: This story is based on 2x07, which I thought had so much more Whump! potential. I've taken out the part where J'ohnn was given the White Martian blood, so he is perfectly healthy in this. The reveal of James as Guardian will also be different – at the beginning of this story he is being framed for the murders of criminals (it's in 2x07). Alex and Maggie's romance is also somewhat paused for this story (even though the drama there is crazy at this stage in the show).

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/KJWriting

Love you guys!

-KJ

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A Darker Side of Cadmus

Chapter 1:

Mon-El was sprinting down the halls before he could even register that his plan had worked. He'd managed to grab the key card from the guard outside his cell and was going to make it. He was going to make it out of this place and back to Kara.

His running came to a stop as he reached a locked door. It was built of the same metal as his cage. He quickly unlocked it and started to push through when a voice forced him to freeze.

"Leaving so soon?" A tall, imposing woman stepped out behind him. The clicking of her heels were echoing through the long, dimly lit tunnel. Mon-El slowly turned to face her. As he did, the door to the left of the hall opened a few feet ahead. Two guards in military-type uniforms dragged another man out of the room. He was groaning, clearly in pain.

Mon-El recognised him instantly. "J'ohnn!" he yelled out, face etched with concern.

"Mon-El, get out of here." the other man gritted through his teeth.

With a smug smirk on her face, the woman interrupted. "If you want your friend to live, I suggest you don't listen to him and stand down." She radiated power.

"Don't listen to her. Run!" J'ohnn called out between his racing breathes. He was instantly silenced with a firm punch to his cheek by one of the guards holding him up.

"No!" Mon-El shouted, jumping forward before stopping himself. "Okay. Okay." He swung his hands up in surrender and dropped the key card he was holding. His main worry now for his friend's safety.

The guards lunged forward and grabbed Mon-El by the arms. "Now that's a good choice.", the woman said. She was clearly satisfied with herself.

They pulled the Daxamite past an unconscious J'ohnn laying on the dirty concrete floor. He didn't struggle against their grip.

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"NCPD has Guardian pinned down near the wharf. They just called for backup." Alex's voice heard through Kara's earpiece as she flew through the sky. They were finally going to catch that murderous vigilante.

"Let's get this guy once and for all." Supergirl stated triumphantly, pushing herself faster through the sky.

Suddenly, a high-pitched hum rang in her head and forced her to stop in her tracks. She put her hands to her temple and tried to concentrate on the deafening sound.

It twisted into perfect clarity. "Hello, Kryptonian."

Of course, it was her. "Cadmus." Kara answered.

"Got it in one." The woman's tone was just plain evil. Supergirl frowned as the other woman began to explain where they got the name Cadmus from, the first Greek god.

"You're crazier than I thought." Was all the girl in the sky gave her in response.

"I'm inviting you over." Kara's eyes darted around in confusion, wondering what this is about. "We already have a guest waiting for you. Your Daxamite friend."

'No.' Kara thought to herself, her heat sinking.

"But if you tell anyone where you're headed, he dies. If you refuse to come, he dies."

She paused her sinister threats for a moment, allowing it to sink in. "Come to me Supergirl. But I should warn you… in the Greek myths, Cadmus was really only known for one thing; he killed monsters."

Kara knew she didn't have a choice. She needed to give in or Mon-El would die. Her heart was racing as she pulled out the earpiece from the DEO and destroyed it in her palm.

Her mind raced as she sped through the sky, headed for the last known Cadmus location she could think of.

She crashed through the large window of the old, abandoned building and landed on her feet inside.

A figure stepped out from the shadows.

"J'ohnn? What are you doing here?" complete confusion covered Supergirl's voice as she asked the question.

"I think the real question is, what are you doing here?" He didn't sound like J'ohnn. His voice was jaded and dark. "I should've locked you in that laboratory when I had the chance."

"You're Hank Henshaw." She said in realisation. "The real Hank Henshaw."

He slowly inched closer to her, "I survived, but that thing from Mars stole my life!" He spat out, rageful. "It took everything from me." He paused, regaining composure. "Cadmus saved me."

"So now you work for them." She stated, putting the pieces together.

"When I ran the DEO, we hunted aliens." He stopped just a few feet in front of Supergirl. "Now Cadmus has inherited that glorious purpose - to end alien life on this planet."

"Good luck with that." She retorted, swinging her fist to strike Hank in the face. The contact didn't have the desired effect. He wasn't thrown of balance at all. He simply turned his head back to face her with a menacing grin.

'That's not possible', Kara thought as her eyes widened with surprise.

"My turn." He growled, back handing her so hard that she was sent backwards into the wall behind her. He stormed after her, picking her up before she had time to recover. She was tossed across the room and into a column as if she didn't weigh a thing.

"Why are you doing this?" Kara asked the man, panting through her pain and shock.

He only responded with yet another grin.

Supergirl rose quickly and swung her fists at him again. Hank managed to block the hits with his forearms, eventually grabbing her by the shoulders. Instantly reacting, she reached for his arms and held on. They were face to face when her heat vision struck him on the left side of his face. He didn't even flinch as the skin melted away to reveal some kind metal and advanced electronics hidden underneath.

"What did they do to you?" Kara asked, unsure what to think at this point.

He shrugged her hands off him and struck her right under the chin. Supergirl was launched backwards, landing unconscious in a pile of rubble.