Assassination Plot is a Horde quest (though Alliance can find the note, they can't turn in this quest because the NPC is a Horde tauren) in Thousand Needles in which the player character finds evidence of a centaur plot to assassinate Kanati Greycloud at Whitereach Post. Leads to 
To Get This Quest Edit
The Tauren, Kanati Greycloud is bold to set up a hunting camp in Thousand Needles. We must kill him to rid this hunting camp and all who may follow him. We will converge at the small post Southwest of the Great Lift.
They come to kill me? I will show them how a Tauren fights!