Because I Don't Like My Big Brother At-All--!! Season 1 Episode 11

Calling Out to Brother from the Center of the World

As Shūsuke puts up with more of Ran's dubious rituals, Rin forces Nao to hang out with her by threatening to tell Shūsuke that she had been stalking him, looking for an opportunity to kiss her. Shūsuke and Nao soon become paranoid around each other when they see each other hanging around the respective Yatagai sister. Nao and Iroha determine that the only way to get Rin off her back is to convince Ran that Shūsuke isn't her saviour by pretending to be prophets on their mobile phones. Rin catches onto their plan and tries to get the drop on Nao but ends up kissing Iroha instead, though she immediately takes a liking to her lips and runs off with her. Ran later explains to Nao that she wanted to mentally train Shūsuke to play as a warrior for a cosplay event, though when the day of the event arrives, Shūsuke gets the address wrong and arrested for wearing his skimpy outfit in public.