Hellmouth is a five-issue crossover between Buffy the Vampire Slayer and Angel that begins after the events of Buffy #8 and Angel #5 when the Hellmouth starts to activate beneath Sunnydale High School.
Mutated rats, snakes, and other creepy crawlies are spewing out of the Hellmouth, turning Sunnydale into a battleground. Giles heads to the Magic Shop to ask Anya for help, while at the school, Buffy and Xander start looking for the source of the chaos. That’s when Buffy and Angel officially meet, inspiring levels of frustration and irritation from each party. But, that doesn’t outweigh the need to find the Hellmouth and stop it from opening completely.
The first issue in this limited series expresses the madness and danger that Buffy, Xander, and their crews will have to face. Writers Jordie Bellaire (who has been writing Buffy) and Jeremy Lambert did a good job of setting up the story with a taste of what scary situations are in store and planting seeds for future conflict and/or alliances.