"Of course," Palpatine says, his eyes filled with wonder. "I'll do it. We'll make the galaxy better together, for everyone you care about, and it'll make it better for me, and I am that kind of person, then. Even in the future, as long as I think you've done me a favor with all of this, with making me immortal, with giving me a paradise - which I will - I'll know that across all time, it's best for me to never betray you. And so I won't."

Plagueis smiles, and for once, it actually has a hint of warmth. "Thank you."

"Now let's apply some of my quickest treatments to those burns, and then get back to your palace. And then in a few weeks, I'll be back to help you kill your family and steal all of their political influence, and then you'll take over the galaxy and create an eternal utopia."

"You've done well, Darth Sidious." Yes, he gets a Darth and a Sith name already, he's earned it.

And Palpatine will accompany him back, and only once he's made it back to the safety of his own room, many hours later, will he finally let out his own real smile.

Because while sure, Plagueis was right, across time and all that, the best decision theory says to cooperate with people who can predict what you'll do, who can make it so that whatever you do then is also what you would have been doing in their predictions...

Plagueis can't predict him.

He might not be trained, but he knows what the touch of the Force feels like. His mind wasn't being touched at all during that encounter, no matter what Plagueis wanted him to think. And Plagueis quite clearly was surprised by a little of what Palpatine did, meaning he's not flawless at predicting people, especially not Palpatine.

He put on a convincing act, and it worked.

So the boy who was once Sheev Palpatine, and is now Darth Sidious, will learn the ways of the Sith, and gain power, and take actions that look to such an imperfect predictor as helping Darth Plagueis bring about his vision - until the second that he's strong enough to defeat him, the second he no longer needs his help.

And then Darth Plagueis will die, and Darth Sidious will reign.