After six days, Blaine had bitten most of his fingernails down to the quick. He had packed and repacked his suitcases, jogged up and down the building's sixteen flights multiple times a day to burn off nervous energy, and spent many hours grooming and playing with Nova. He also fed Groucho and cleaned up after him, but otherwise ignored the electric animal in favor of the genuine one. A few times, Brittany came with him, learning the care of the animals that would soon belong to her.

Tina had left four days ago, when sharing a bed with Blaine had become too awkward to bear. Finn Hudson had been on the roof taking care of his horse the day Blaine waited with Tina for the hover-taxi. He watched Blaine load the small suitcase into the back and saw their brief, awkward hug just before Tina climbed in and the taxi took off, leaving Blaine on the roof alone. When Finn asked where Tina was going, Blaine said she was taking care of a sick friend for a few days. Blaine wasn't about to tell the neighbor that his wife was living temporarily with her lover. He would let her handle the uncomfortable explanations when he left for Mars and she and Mike moved back to the apartment.

In the meantime, Blaine spent each evening holding an uneasy vigil in Brittany and Santana's apartment. Brittany treated him like an injured animal – speaking softly, smiling broadly, and encouraging him to eat and to rest. Santana circled him like a vulture, waiting for moments when Brittany was out of earshot to toss out stinging barbs of mockery, laughing at him for continuing to wait for someone she swore would never come.

Blaine had been dozing on their couch for almost two hours on Wednesday night when a staccato knock startled him out of an uneasy sleep. Brittany and Santana looked at him expectantly from the hallway. As soon as he made eye contact, Santana wrapped an arm around Brittany and steered them both backwards toward the bedroom with slow, silent steps.

Blaine sighed and rolled his neck, cringing at the loud pop. His limbs felt unwieldy as he dragged himself off the sofa and took a few heavy, uneven steps.

Another knock rang through the air and Blaine's entire body twitched at the sound, much louder now that he was almost at the door. He drew back the bolt and swung the door open immediately. He was sure it would either be Kurt or Carson, but he realized as the door opened to reveal the familiar figure that it would have been better to ask who was first. It would have saved him the embarrassment of having to guess. Blaine took in the man's appearance head to toe, searching for clues. He wore a standard overcoat with built-in safety features to shield him from the radioactive dust. Dark jeans hugged his calves and his shoes were dressy, but not overly fashionable. His hair was swept back but windblown, the original style difficult to discern. His eyelids drooped over pale blue eyes, weary with exhaustion and underlined with puffy, dark bags.

“Kurt?” Blaine asked uncertainly.

“It's time to go,” Kurt said brusquely, pushing past Blaine and striding into the apartment. “Have you made your arrangements?” He spun around, surveying the empty living room and kitchen “Where is your wife?”

“She's not coming,” Blaine said. “She – um. She found someone else.”

“Oh,” Kurt said, still glancing nervously around the room. Almost absently, he added, “I'm sorry.”

“No,” Blaine said quickly. “It's not like that. I'm happy for her – mostly. We're better as friends anyway.”

“That's good,” Kurt said, stepping out of his overcoat and holding it out toward Blaine without looking at him. Blaine took the coat, folding it over one arm. Kurt was dressed very simply in form fitting blue jeans and a black t-shirt.

“Your arm,” Blaine said questioningly, stepping forward and curling his free hand around Kurt's bicep. He rubbed his thumb gently over the smooth skin. Kurt jerked his arm out of Blaine's grip and took a step back, his eyes wide.

“Carson?” asked Brittany, stepping cautiously from the bedroom door and tugging Santana into the hallway after her. Kurt squinted at each of them for a long moment before acknowledging them. “Brittany, Santana,” he said, nodding at each of them.

“It is Carson!” Brittany exclaimed with a knowing look at Santana, grinning. “I knew it would be you,” she said, bounding forward and throwing her arms around him in a tight hug.

“No, not Carson,” he said, extricating himself from her limbs and stepping out of her grasp. “I'm Kurt.”

“Bullshit,” said Santana matter-of-factly. “You're not either of them. You had to think about our names. Don't think I didn't notice you studying us. The gears turning in your brain as you matched up the names you memorized with the appropriate hair colors are visible from space, Imposter. You might as well have just called us the blond and the brunette. Besides,” she continued, pointing at him accusingly, “last time we saw Kurt he had a gaping wound the size of Texas on his arm.”

“I heal quickly,” the man said dryly.

Blaine, Brittany and Santana traded skeptical looks. The man ignored them and asked, “Isn't Carson here? I left him with you.”

“No, he's been missing for days now,” Blaine said. “We thought Ku – you might know where he is. I have paperwork for him that might help him stay safe.”

“Oh,” the man said mechanically. “I guess he thought he'd be safer on his own. I'm sure he's made it at least to Canada by now.” He picked a thread off his shirt and flicked it unceremoniously to the floor. “I don't expect you'll see him again.”

“I'll miss him,” Brittany said with a small sniff.

The man just stared at her with a puzzled expression, as if trying to work out the mechanics behind one person missing another. Blaine looked down and realized he was making fists so tight that the veins of his hands were popping angrily to the surface. He forced himself to breath and stretched his fingers open wide. His fingernails left crescent-shaped welts on his palms and he rubbed them for relief, first one hand and then the other.

“Why didn't the Association stop him before he killed almost all of my friends?” Santana shook her fist at the man and shouted. “Or better yet, why did they make me like this? Huh? Tell me, Mr. Imposter. If they can just stamp out endless identical versions of Santana and Kurt – one after the other for eternity – why did they have to make me care about what happens to my life? Couldn't they have made me happy to stay on Mars, to be a slave to a human who didn't care about me?” Santana's voice cracked as she shouted, tears glistening in her eyes. Brittany wrapped an arm around her and rubbed comforting circles onto her arm. “You and all the other Kurts and Carsons. Me and all the other Santanas that are out there. We look exactly alike, just like ants. Why can't we be like ants and not feel so damn much!”

The man looked somewhere past her and said so softly that even Blaine, standing right next to him, could barely make out the words. “They may stamp us out like ants or bottle caps, but even they can't keep us from being unique. We're so complex that we're bound to evolve, to have our own memories, to matter.”

“What the fuck are you talking about?” Santana spat out through her tears.

“Come on,” Blaine said, stepping toward Kurt and placing a hand at his lower back. “It's time for us to go. I have everything ready for the trip. We can grab the bags from my apartment and go to the shuttle right now.”

“Are you out of your mind?” Santana said. “He's as good as admitted that he's an imposter. And you're going to take him with you to Mars?”

“Yes,” Blaine said coldly, still guiding the other man toward the door. “He looks and sounds like Kurt, and that's good enough. I guess you were right about me, after all.” He grabbed the other man's hand in his and swung the door open. “Goodbye Brittany. Goodbye Santana.”

“Goodbye,” Brittany said with a wave, a confused half-smile playing on her lips. “I hope you have a good trip.” Santana stood sullen and silent beside her.

“Come on, Kurt,” Blaine said pointedly. “Let's go to Mars.”