Rakka works with Nemu at the library to find her place in life and renews her curiosity about the outside world. Kuu, a younger Haibane who is normally bright and cheerful, helps Rakka to find her place in the Old Home, but then becomes subdued and her halo begins to fade! Rakka's worries become a desperate search when Kuu goes missing is this somehow related to the "Day of Flight" overwhelmed with sadness, Rakka is further shocked by a revelation about Reki's past!