I Won't Betray Their Efforts - S1.E4

As the 77th gen trainees arrive on Akibastar, they are brought to see an AKB concert, which is opened by the two remaining 75th gen trainees, Mimori Kishida and Sonata's older sister Kanata. However, Kanata is not too pleased that Sonata had joined up and ends up arguing with her. Speaking with Mimori, Kanata reveals she joined AKB so she could get revenge on the DES for killing her father and did not want Sonata to face such danger. As dance lessons begin the next day, Kanata becomes frustrated when her instructor criticises her lack of motivation and runs off. However, Mimori reminds her that it is okay to enjoy singing and she soon makes up with Sonata.