Mikawa is the real hero of this story. She handles getting unexpectedly turned into a third wheel with a night out with her best friend very gracefully.
Also seriously did the authors really try to portray her going two feet away to talk to her friends for like thirty seconds as a terrible moment where Yamada was forlorn and abandoned and Kase needed to rush in and rescue her?
God, this manga. Yamada wants Kase to be with her at the fireworks, so... instead of talking to her and seeing if the schedule would work out, she just silently goes and hopes real hard and magically Kase just shows up. And she ends up not beign able to walk, so if Kase hadn't shown up... what, she'd have to have been stretchered out?
I'm REALLY over this Magic Knight Saves Helpless Innocent Waif fantasy the author is continually re-enacting.
God, I honestly cannot understand anyone not finding it the creepiest thing in the world that Kase came because Yamada was wearing a yukata and therefore had to be protected, and not because she just wanted to see her girlfriend for a nice night. In any other story, that'd be an ominous sign of darkness to come. Here, it's about, "If a gross old man hits on Yamada at a festival in Tokyo, it'll risk chipping away at her sweet innocent purity (and it's Kase's job to do that)."