Everyone has their price, and in Kobato's case her price seems to be some limited edition anime merchandise. Don't worry Kobato, you're not the only won.
Anyway, the reason that Kobato has to be bought off at all is that Sena has managed to snag some tickets for a theme park, and of course she wants to take Kobato along as a treat. Thankfully for her, the rest of the group also expresses an interest in going so before we know it the entire thing turns into a day trip for the Neighbours Club - a trip which involves a mind-breaking trip on a roller-coaster as one of its highlights.
The day also provides another opportunity for Sena and Kodaka to get a little closer to one another, although of course Sena is so tsundere about the whole thing that no real progress is made on that front, even when the two of them are mistaken for Kobato's parents. Once Yozora and Sena's rivalry gets fired up again, the aforementioned roller-coaster becomes their battleground, with.... nauseating results. After (and let's not beat around the bush here) being spewed upon copiously by the two girls, there's nothing for it than for the group to head off to the baths (do Japanese theme parks usually have baths? Genuine question) - a simple affair you might think, but one which reveals a shocking truth about Yukimura. Okay, okay, so it's shocking to nobody but hey, our suspicions are now confirmed and Kodaka can now feel a little less guilty when his body runs away with him.
As it goes, this was another passable episode of Haganai - it managed to keep Yozora and Sena from tearing strips off of one another too much, and ignoring the suggestion that Yozora had rather a lot to do with Yukimura's gender confusion (which would be another low for an already disagreeable character) this was a relatively entertaining episode in terms of simply allowing its characters to bound off of one another. The trouble is that we basically know all the jokes that this series can pull by this point, which makes the whole thing a little too predictable - unless the show can find some smart ways to shake things up (and no, Yukimura's gender doesn't count) then it has little hope of offering anything other than occasional glimpses of good humour. I'm not hating watching this series - I'd have dropped it if I were - but its halcyon days were surely over long ago.