Scar / Illness / Arrival of Winter - S1.E7

Rakka refuses to believe Kuu will never return from her Day of Flight, and sickly black spots begin to appear on her own wings. Depressed, she goes to town alone and is approached by Hyouko, a Haibane from Abandoned Factory who asks about Reki. Reki gives Rakka medicine for her wings and tells her about the Sin-Bound Haibane and about her own past.