In a nutshell: Buffy is pregnant - who's the father?
Here's a link to a full recap (big thanks to Zianna!)
Apparently, the action takes place the next day after the events of the first arc, including the night of the party when Buffy (apparently) had sex with somebody (in issue 4 Buffy's roomies decide to talk to her about weapons in her room; in issue 5 they try to talk to her). In real life, pregnancy tests don't work so quickly. Are we supposed to suspend our disbelief and assume that Buffy was knocked up during the party? (Scott Allie said in Q&As that the party will have consequences, but, as usual, his answer is open to interpretation.)
If so, we have at least seven suspects: Xander and Riley (she spent some time with both of them); Buffy's boss; her mysterious neighbor, Heinrich whom nobody saw and who sent her flowers the next day; Andrew; Spike (maybe his bugs used some advanced medical methods when they were treating his wounds :). And, let's not forget about the elephant - I mean Angel. He already has two children - Connor and Kitty Twilight. Three's a charm. (He could have knocked her up in season 8, but her slayer essence was blocking the development of the foetus - until Severin took it away, if we assume that Severin's de-demonizing process starts with reproductory organs).
In any case, I'm sure that Joss' choice of father was based on the principle of maximum pain for Buffy. And if the previously established rules stood in the way of the story he wanted to tell, he bended or rewrote them.
So far, the most likely candidates are Angel and Heinrich. Angel, because it would be very painful for everybody involved for obvious reasons; Heinrich - because he's a dark horse and Joss can go in any direction (Heinrich could be a demon; an anti-slayer activist with an agenda; a time-traveller from the future who is a recluse to avoid changing the timeline) to bring on the angst.
Then again, Heinrich-as-a-father can be The Immortal of season 9 - just a faceless plot device to keep the shipping status quo intact.
Another question is where do we go from here. Given the history of pregnancies in Jossverse, I expect all kinds of horrors. Buffy's enemies will try to kill/abduct/sire her baby. Or Buffy finds out that her baby is evil. Or that she has to sacrifice her baby to restore magic. Or she will have twins Melaca and Harth whom time-travelling Heinrich takes to the future in a mission to save humanity.
Or something even more heartbreaking will happen. Joss has a carte-blanche here. "You must save the prince". "Unlock the key [to bring magic back]". "You're not the slayer". There is a lot of random clues that point to global importance of Buffy's pregnancy.
I looked through Google links for "female monomyth" + "pregnancy" and couldn't find anything interesting. Apparently, it's pretty uncharted territory (except Xena, of course).
Looks like the season will be quite a ride, after all. Time to buckle up.
I hope DH and Whedon will pull it off. Overall, the issue is very good. Moline's art suits better to the storyline about Buffy becoming a mother, because he draws her with more womanly proportions. I wonder is Joss plans to compress the timeline - for example, they make a break after May issue -- and the next, August or September issue will feature Buffy with her already-born baby.
And to cheer up from all the gloom and doom - a rec for a funny fic that kinda reflects current situation: The Completely True Story of Buffy, the Slayer of the Vampyres as told by A.W by st_salieri