After Buffy dies in season 5, in which episode in season 6 does Giles come back?

If my memory is all good he leaves in season 6 episode 8 "Tabula Rasa" and then comes back in episode 21 "Two To Go".
Hope that helps. :)
(woops had to edit coz I put season 5 instead of 6... lol)
Also if u wanna check u can look on imdb link and see the list of every episode that Giles has been in..