After his depressing encounter with Hanekawa earlier that day, it's time for Araragi to pay Shinobu and Oshino a visit, proferring his blood for the former and some doughnuts for the latter. At least, that's the plan...
Instead, this is the point where we discover Shinobu's sweet tooth and love of said doughnuts - something to which she's willing to go to decidedly un-vampirelike lengths to procure from Araragi as Shinobu's behaviour as a sullen child turns into something more akin to a hungry dog. This is but a distraction from more pressing matters however, that being Hanekawa's problems at home - something which Oshino quickly picks up on despite Araragi missing out certain details, in a story that takes a worrying turn in Oshino's mind once Araragi relates how Hanekawa had found and buried a dead cat just before they parted ways.
Of course, this being a prequel as it is, we already know what this means - that an oddity has attached itself to Hanekawa, and while Oshino heads off to confirm this possibility at the location where the cat was buried, it's up to Koyomi to check in on Hanekawa herself. What Araragi finds instead is something altogether more troublesome, a part-feline individual prancing around in some very familiar underwear - what's more, she's done some serious damage to Hanekawa's "parents", and has no compunction about ripping Koyomi's arm off in a flash. While this wouldn't normally be a major issue for our protagonist, the fact that this particular oddity carries the same "Energy Drain" ability as a vampire does some equally severe damage to his ability to regenerate.
With its line in incestuous fan service out of the way, this second instalment of Nekomonogatari feels far stronger than the first, and more importantly it feels far closer in tone to Bakemonogatari - something which serves it in good stead as it builds up the real crux of its story here. Hopefully now that a fire has been lit under this story the second half of this outing will be remembered more for some decent story-telling and characterisation than pandering to the fans.