|S2 Episode 4 - A Man Is Among Them!|
That guy who called Kotaka at the end of ep3 was actually his dad, and he says it was Sena's dad's drunken ramblings that made him think he was marrying Sena.
Sena invites everyone to a theme park. Yukimura is the only one who's perfectly calm on the roller coaster ride, and Maria wanted to go on it again after.
Sena took Kobato and Kotaka to a stage play, and she was trying really hard to act like Kobato's big sister and being nice to her, and her and Kotaka got really agitated when someone thought they were Kobato's parents.
Sena and Yozora started riding the roller coaster over and over again to compete with each other, and then they puked on Kotaka. Then they all go to a bath, and Maria goes to the boys' side because she doesn't want to be with the puke-smelling girls. She then points out that Yukimura doesn't have a thingy like Kotaka does, and Kotaka realizes that Yukimura was actually a girl all along. Rika manages to convince Yukimura that she's actually a woman. She says she thought she was a guy her whole life because of "family circumstances", and thought that she just needed to train more to become a proper guy.
That was a really weird unexpected development... and now Yozora is pissed because she has both Sena and Yukimura to compete with over Kotaka.