This comes from www.episode-x.com , I hope it's not an April Fools joke.
After Obi-Wan’s capture by Droids he is brought into a dungeon, where he is held captive, suspended in midair inside a blue force field.
Count Dooku enters the room, very suave, saying that there has been a terrible mistake. “They've gone too far. This is madness.”
Obi-Wan counters that he thought he [Dooku] was their leader, to which the Count quickly replies that this has nothing to do with him, and that he promises to petition immediately to have him set free.
Obi-Wan cynically remarks that he hopes it doesn’t take too long, as he has work to do.
Dooku now changes his approach, saying it’s a great pity their paths have never crossed before. “Qui-Gon always spoke very highly of you. I wish he were still alive. I could use his help right now.”
Obi-Wan shoots back that Qui-Gon would have never joined him [Dooku].
“Don't be so sure, my young Jedi. He was once my apprentice, just as you were once his” counters Dooku, who goes on saying Qui-Gon knew all about the corruption in the Senate. “We would never have gone along with it if he had known the truth as I have.”
Obi-Wan carefully follows. “The truth?”
At this point Dooku drops the shocker. “What if I told you that the Republic was now under the control of the Dark Lords of the Sith.”
Obi-Wan is dumbstruck. “No. That's not possible. The Jedi would be aware of it.”
Dooku explains that the Dark Side of the Force has clouded their vision. “Hundreds of Senators are now under the influence of a Sith Lord called Darth Sidious.”
Obi-Wan doesn’t believe him.
Dooku continues, revealing to the Jedi that the Viceroy of the Trade Federation was once in league with this Darth Sidious, but he was betrayed. “He came to me for help. The Jedi Council would not believe him. I've tried many times to warn them, but they wouldn't listen to me”. Dooku tells Obi-Wan that he must join him and together they can destroy the Sith.
“I will never join you, Dooku.”
Dooku realises now that there is no chance persuading Obi-Wan and leaves him to his doom. “It may be difficult to secure your release”.
Though it seems like an April Fools joke cause Dooku reveals alot to Obi-Wan.