Voir Yosuga no Sora: In Solitude, Where We Are Least Alone, Season 1 - Episode 7

Ryouhei and Haruka are on the school rooftop, peeking at the girls cleaning the pool. Haruka warns Ryouhei not to peek at Nao, and leaves. Much later Ryouhei tells Nao that Haruka has a crush on her; all the while she had been thinking that he did not like her. Something had happened between the two many summers ago and Nao is feeling guilty so many years later. Meanwhile, Sora shows her hatred of Nao, whom she thinks is the reason why Haruka has been preoccupied the past couple of days.