Celty dwells on her missing piece and Ryuugamine gets an unwelcome visit from some representatives of shady Yagiri Pharmaceuticals.
There aren't many passive characters in this series, though some do prefer to observe more than others. But underneath, they're all acting on their own inclinations, following their intuition, and shaping their own stories. It's just that they're all bound together by the interconnectedness of their crazy neighborhood, and so bound to influence one another. Nothing's ever static in Ikebukuro, which is one reason Ryuugamine's so drawn to it in the first place (and why the reader doesn't mind hanging out on the corner to see what happens next).