Seeing Kara so terrified shook Alex to her core. Sure, she'd seen Kara scared and hurt, and she always worried about her because she was her little sister, but this had been different. Alex couldn't imagine the horrors Kara must have endured to bring on such a visceral reaction. She'd been so scared and angry that she almost blasted Lena with heat vision.

Alex had wanted to run and protect her, hold her, but she knew she wasn't who Kara needed at that moment. She needed her wife. Lena knew the details; Kara had opened up to her.

Part of her missed the days when they would sit in her apartment living room and talk about anything and everything over a beer and some takeout. But it was partly Alex's fault they had grown apart. She'd gotten into a relationship with Kelly and Kara had found Lena.

Alex swallowed her pride and selfishness for wanting her sister to herself, and instead focused on how happy she was to get to see her little sister again.

Kara had her best friend, her wife, and she was alive.

Alive.

She glanced at Kara and Lena whispering to each other, Lena standing between Kara's legs as she sat on the edge of the lab bed. Kara's smile was soft, and though her eyes were shadowed, they sparkled as she beheld Lena.

Lena was a good woman. A strong woman. She'd stand by Kara until the end of time. Alex couldn't ask for a better woman to be by her sister's side. She was grateful to the stars they had each other. They deserved each other—deserved to grow old together and live out their days in happiness.

"Alex," J'onn said quietly, "may I have a word?"

She nodded, glancing once more at her sister before she followed him into the hall.

J'onn peered past her shoulder and then exhaled, arms crossed. Alex gazed up at him, head tilted. "What is it? Something's wrong?"

"Alex," he said, shaking his head, "Kara's mind was a mess. It's like nothing I've ever seen before."

"I gathered as much from the little bit I know."

He raised a hand, fingers pinched together. "An individual's memories have their own markers, usually in the form of a color. Kara's are golden, bright. Like sunlight."

Alex wouldn't expect any other color for her. "But?"

J'onn exhaled again. "My memory…aura, if you will, is green. When I went into Kara's mind but a few minutes ago, pieces of my markers were deposited in her consciousness like bits of mud falling out of the sole of a boot. When I went in, those golden memories of Kara's had been mixed with dark, cold ones. Remnants left by another person who had been in her mind."

"Sud-Aletheia," Alex muttered, jaw working as her blood boiled.

"It wasn't just that he had been in her mind, but he had taken pieces of her memories and melded them with his own. Some memories were so re-worked, so changed that I couldn't tell the two different markers apart."

Alex thought back to a few hours ago when Lena had found Kara in her apartment hallway hunched over, hands shaking, and repeating one word: gone.

Gone, gone, gone, she'd muttered. It was like she hadn't even been aware of where she was. Like she saw a completely different reality.

Alex ran a hand through her hair and sighed. "That's why Kara sometimes looks like she doesn't know if we're really here? Why she sometimes seems so desperate she looks like she'll claw her own skin off?"

J'onn nodded. "I don't know how Sud-Aletheia did this, but he managed to take Kara's own memories and morph them into his own creation. He turned her memories against her." He shook his head. "She's been living with mutant memories for months."

Alex's throat bobbed. "Oh my God."

He glanced into the lab. "That wall I shattered to return Kara's memories was only the start of it. Those were memories she had suppressed herself. She could have gotten those back without me, but I quickened the process."

Alex slapped a hand to his shoulder. "Stop it. Just tell me what's going on."

He ran a hand over his closely shaved head. "Do you remember when Kara came to us about two years ago? She'd been plagued by dreams of some shadow figure who always appeared briefly and then disappeared as soon as someone else in her dream died."

"Yes," Alex nodded, remembering the call she'd gotten from Kara the first time it had happened. "It was the same thing every night. She stopped sleeping, became irritated and paranoid." She gaped at J'onn. "And then one night it changed. It freaked Kara out. She woke me up and then we both came to you."

"Kara told me she'd seen too much," J'onn whispered, "and she asked me to—"

"Lock away her memories," Alex breathed.

He nodded again.

"All the pieces are starting to come together." Alex pulled J'onn with her as she walked. "You think the dreams may have been of Sud-Aletheia?"

"It's certainly possible. When I locked those memories away, even I couldn't see who or what lay within them. She'd somehow shielded them from me. Instead of letting me in, she had simply instructed me on which ones to keep from her."

"Sud-Aletheia must have been looking for something within those memories. That must be why he kept her for so long. He was trying to get through your barriers."

"With the damage he caused Kara's mind, I'm impressed he didn't."

Alex turned back as if she could still see Kara. "I think I'm more impressed with the fact that she's not in shambles."

"She is," J'onn sighed. "She just doesn't want you to know."

Alex closed her eyes. "Always the strong one fighting for everyone but herself."

"We need to let her know that we're here," he said. "That we're willing to fight for her. For once, she needs to let us in."

"She came to you for help," Alex shrugged. "I think that's a start."

J'onn put his hands on his hips and hung his head. "None of this makes sense. Why would Sud-Aletheia, this alien who—and we don't even know the extent of his powers—let Kara go? Why let her think she escaped?"

Alex shrugged. "I agree. None of this adds up." She looked to him. "Perhaps the answers are in whatever you locked away. Kara wouldn't go to such lengths to hide something if it wasn't important. Does she even know you did that?"

J'onn shook his head. "She instructed me to lock away any and all memories pertaining to the dreams and whatever else she'd said. She doesn't even remember having the dreams, let alone remember coming to me to shut them away."

"What would happen if you unlocked them now?"

"Well, if I even can," he said, brows raised. "The mind is a powerful thing, so I could go in and attempt to free those memories and Kara's subconscious could fight me off like she tried to do earlier." He sighed. "If I liberated those memories, I don't know what would happen. Her mind could collapse or shred itself from the inside out to protect Kara's psyche."

Alex grimaced. "Here's what I don't understand. If Kara doesn't know about any of this—if those memories you locked away do pertain to Sud-Aletheia and whatever he's spent nearly two years looking for—then why let her escape? Why not continue trying to break into her mind?"

"Maybe Sud-Aletheia knows he needs a key, and he knew that Kara would unknowingly lead him right to it. Hence, a fake escape."

"A key? What do you mean?"

J'onn stared at Alex, expression grim. "I'm the key; I created the lock and I'm the only one who can unlock it."