Despite the last three volumes having different writers they've all held deliciously true to the Buffy-verse while not letting the storyline becoming dull or repetitive. With this addition the story moves the focus back to Buffy and to the large story arc, Buffy vs the mysterious Twilight. Except it moves at this plot from a side arc rather than straight forward.
It cannot be coincidence that a temporal anomaly sucks Buffy into the future right when Twilight has been trying to convince her of the futility of her spell to make all the Potentials into genuine Slayers. Whoever Twilight is, they are fighting to kill Buffy, to destroy the spell so the balance between good and evil will be restored.
So whether the anomaly and Buffy being present is due to Twilight's interference or not, Buffy landing in a future words where a Slayer is at war with her twin, who has been turned into a vampire, seems only to reinforce Twilight's attacks on Buffy's resolve.
But the main player in this tale doesn't appear to be either the strange, lonely Slayer, her vampire twin with the Slayer's memory, or Twilight. Instead the direct story behind Buffy's time trip is sadder and closer to home than Buffy could guess.
While ultimately a sad volume, so much is left undone, unexplained, unseen or heard that it takes from the depth of the final scene. Readers can only hope that the Buffy-verse continues its habit of baiting, teasing and most of all, delivering.