Buffy Summers is hip, modern, and pop culture savvy. Rupert Giles, her Watcher, is a stuffy Brit whose idea of bliss is a good book and a strong cup of tea. Odd as the duo may be, though, they have managed to avert their fair share of apocalypses. Plural.

One thing they can't seem to conquer, however, is Buffy's bad birthday luck. At eighteen, Buffy is subjected to a Watcher's Council Cruciamentum, a test of her own non-physical wiles -- and of Giles's attitude toward both his charge and his calling, as well. And when the Slayerettes throw a surprise party for Buffy's big 1-9, Giles finds himself feeling useless and out-of-the-loop-y. But it is at the Slayer's twentieth birthday gathering that both Buffy and Giles are forced to re-examine the nature of blood ties and the definition of family -- or risk losing a mutual loved one more important to them -- and the fate of the world -- than either ever imagined....