Buffy the Vampire Slayer: Hellmouth #3, Buffy the Vampire Slayer/Angel: Hellmouth

Angel and Buffy are on a mission to find the Mistress and close the Hellmouth—but will they turn on one another first? And is Drusilla the true evil behind the Hellmouth, or if there is another, even more powerful, that they should be worried about? Spoiler: there is.