A not-very-short note before the story begins: Ignore why the Master's alive. It's the author's whims. Therefore, he is alive again, looking like the Simm Master still (Harold Saxon). Also ignore how the Master found the TARDIS and how the Doctor knew that he was going to meet the Master. They're not important.

Additionally, the Tenth Doctor didn't regenerate into the Eleventh, because I prefer Ten/Simm!Master over Eleven/Simm!Master (or any other Master, for that matter). I tried to write for Ten's personality, but I think it ended up as more of an odd blend of Ten and Eleven. Also, I think I wrote the Master OOC. I am so, so sorry.

"You're going to make regular people jealous, Master," the Doctor said nonchalantly, teasingly, though inside his hearts felt like they were simultaneously breaking and healing. "You've cheated death three times now, not counting your normal regenerations."

"But since when have I been regular people, or even regular Tim Lord, Doctor?" The Master's voice was biting, sarcastic, but there was a lightness to it that hadn't been there since they were both young on Gallifrey.

"So, are you still with that blonde? Picked up any new friends while I was gone?"

"If you mean Rose-" he ignored the Master asking with mock horror, "How many other blondes have there been?"- "She's… no longer here. She's in a parallel universe. And I do have some companions. They're in the TARDIS right now."

"Why? Had to protect them from the scary old Master?"

The Doctor closed his eyes, a faint expression of sorrow flashing across his face for a moment. He opened them again and focused on a spot over the Master's shoulder. "I thought that maybe I should handle this on my own. Personal issue."

Silence followed this comment and the Doctor shuffled awkwardly. Finally, he voiced one of the many questions spinning through his head. "Why are you here?"

For a moment, the Doctor saw a flash of Koschei, the sort of vulnerable expression he used to make when he had too much pride to really appear weak, before it was masked over. There was still a hint of it left, tugging at his memories, begging him to give in, shed all the responsibilities that weighed him down, and just be Theta. The Doctor was too broken to throw himself at the Master (Koschei) and sob for everything, the fate of planets, companions, them, all the pain in the universe, like Theta would.

"I… I've come to take you up on your offer," the Master said, strains of arrogance that could not be killed weaving through the words. "To travel through the universe and see galaxies."

"But… why?" the Doctor breathed.

"I'm sick of the game we're playing," the Master admitted quietly, "I'm sick of trying to get you to notice me. You abandoned me, and I'm stick of trying to stop you from doing it again." He sounded just like Koschei. "But I can't… I can't leave. Not when you gave me that stupid hope that you would take me with you."

"I won't abandon you again, I promise. I always, always wanted you to stay with me. I never forgot you, and I never will. Come with me?" Hope. He hadn't hoped in so long, not for this, and now it was more than just hope.

The Master- but he didn't seem like the Master anymore, more like Koschei- choked out a laugh. "That doesn't have to be a question."

Theta and Koschei's lips met halfway.

"Amy, Rory, this is the Master. Master, Amy and Rory."

"Hi," Rory supplied awkwardly. The Doctor scuffed his shoe along the floor. Amy finally broke the silence.

"So Doctor, why's he here?"

"Well, he's going to be joining our little group…" He trailed off, feeling like a better introduction was in order.

"I'm his boyfriend," the Master added helpfully.

"That sounds so… boring." The Master shrugged neutrally at the Doctor's complaint.

"I'll be going to bed now," the Master said, somewhat aggressively, as if daring anyone to tell him, "No, we're going to save the human race again!"

"Yeah, I'll be going too…" Amy winked.

"Enjoy yourselves!"

The Doctor sputtered, "N-nothing like that!" at the same time the Master said smugly, "We will." They turned to each other.

"What reality are you living in?"

"You don't have to make it so obvious!"

"It's not like it's a grand secret."

Amy grinned as she spun the two around and pushed them towards the hallway with the Doctor's bedroom in it.

"Bye!" she said brightly. The Master grabbed the Doctor's wrist and pulled him down the hallway. They gradually faded out of view (it was a rather long hallway).

"Well," Rory began.

"So."

"Yeah."

They couldn't undo what made them who they were. They were still the Doctor and the Master.

But they were Theta and Koschei, too.