It begins in 1880, a newly sired Spike is still fresh on the game and is introduced to the veteran and infamously brutal Angelus. In Spike, Angelus sees a potential protogé and begins to mould him in his image to create what was to become the second most barbaric vampire in history. However, their relationship hits rocky grounds when Spike walks in on Angelus having sex with Dru, and is outraged seeing as he had earler told Angelus of his intentions for her.
While in the present, Spike recieves a mysterious package from an unknown person, which when opened released a flash of light which made him corporeal once more. However, now with two champion vampires in existance (Spike becoming a champion after the actions of Buffy finale 'Chosen') the universe has been thrown into turmoil, and this is manifesting itself with members of Wolfram and Hart randomly atacking other employees for minor reasons.
To find a solution to this they consult with occult expert Sirk who reads to them a section of the Shansu prophecy which tells of the 'Cup of Perpetual Torment' which the vampire with a soul must drink from it to fufill the prophecy. Hearing this, both Angel and Spike race to it's location in the Nevada desert, followed by a fight which culminates with Spike beating Angel and having the oportunity to dust him, but passes it up because he didn't want to deal with Buffy about it afterwards.
Spike then drinks from the cup to find it out was all a set up, and return to Wolfram and Hart to find Sirk has done a runner and that the Senior partners have temporarily sorted out all the earlier problems. It finishes with Eve meeting with the mastermind behind this entire chain of events, who turns out to be a familiar face from the past who seems to have moved up in the world of the occult.