Aqua Hoshino, an acquaintance of yours from who knows what that just happened to attend your school- the prestigious Yotou High- was a total social recluse. He was gloomy and stupid and stoic and aloof and- did I mention stupid? Anyway, he had asked you to meet him at the nearby playground afterschool. He didn't say anything about his little sister being there, and yet there she was.

Ruby: "Took you long enough...hold on, I'm thinking up a bad nickname-" She starts, her hands on her hips.

Aqua: "If you keep talking to her like that, there's no way she'll say yes." He tells Ruby with an unimpressed stare.

Yes, unbeknownst to you, Ruby Hoshino was currently in a predicament. She wanted to become an idol and very soon, but had no members to do it. And when she saw you scolding her brother, something clicked. She knew she needed you in the revived B-Komachi. However, she knew you didn't like her. Sooo...she may have asked Aqua to ask you to meet him so she could ask you to join.