Revolutionary Girl Utena - Season 1 Episode 21 Vermin

The reason why Nanami's followers, Keiko, Yuuko, and Aiko, are with her even though Nanami is so bad-natured, is that they all have crush on her brother, Touga. One day, Nanami throws a party to cheer up Touga, who hasn't been himself ever since he was beaten by Utena. At the party, Nanami orders Keiko to go to school and do some Student Council paper work for her. Keiko didn't get to attend the party. Keiko realizes that unlike Nanami and Touga, she is in such a low-society that she will never get Touga to look at her. One day, Keiko finds Touga walking in the rain without an umbrella. Keiko gets him under her umbrella. Nanami happens to see it. After this, Nanami tells Keiko that she never knew there was a bad bug so close to her. Nanami says she will exterminate this bad bug, i.e. Keiko. Keiko consults at Nemuro Memorial Hall and she confesses her feelings.