The moment Dooku became the Sith Apprentice. (Warning: Do not let Palpatine play with your hair.)
"Join me." Palpatine's voice was perfectly calm and reasonable. The suggestion was outrageous. (Once, the thought of leaving the Jedi would have been outrageous.) The Senator's hand was extended and steady, empty and inviting and promising.
Dooku eyed the hand and then stared levelly down into the other man's eyes until their depths almost showed unease. He kept his own thoughts veiled.
This man's apprentice had killed Qui-Gon.
He thought that in this man's presence, he would find it very easy to reach for the Force through hate.
He thought that he would find it easy to kill him. Simple.
Less simple afterward: he would have killed the Supreme Chancellor of the Republic based on evidence no longer available, the word of his victim. He would, in all likelihood, be tried and convicted. The Jedi would be embarrassed. He found that he did not care. They could repudiate him. Unhinged, perhaps. Jedi did not seek revenge.
The Sith would be dead.
But would it be enough?
He had studied the Sith, their history, all the Jedi knew of them now. He knew one thing more important than all the rest.
The Sith had secrets.
He could feel the cool curve of his lightsaber against his palm, though he was not touching it. He could feel its sweep....
He gripped the hand.
And then Dooku was kneeling -- purely ceremonially, of course -- at the feet of the revealed Sith Lord. He was mouthing a vow he did not mean and thinking very calmly that he could not yet kill the Sith, because he needed more information. It was fortuitous that he was free to collect it. It would be foolish to act precipitously now; after all, the Jedi had believed the Sith destroyed for a thousand years. Empty promises and a little time would be a small price to pay to avoid that. Besides, how often had they told him he was too resistant to compromising with politicians?
Darth Sidious's fingers rested lightly on Dooku's bowed head, moving gently like spiders in silk to push the hair aside. Dooku listened without much interest as the Sith made a show of contemplating an appropriate new name.
"I will be honored by your service... Darth Tyranus."
That was easy.
Then the fingers in his hair plunged irresistibly inward, driving deep into his mind, a black fecal root. There was no pain, though it took his breath away as if there were. After the first instant of shock it felt as if Sidious's mind had always been inside his own.
Dooku hid from both his Master and himself the first thought that perhaps he had made a mistake.