SAO: Unanswered Butterfly Drops 19-Minute Preview Ahead of Echoes of Aincrad

Sword Art Online: Unanswered Butterfly is a 110-minute feature-length promotional anime by Polygon Pictures for Sword Art Online: Echoes of Aincrad. A 19-minute preview is available to watch until July 5 at 23:59 PDT and will be removed afterward. The story follows Emirun and Rex in a deadly VRMMO, who, with guidance from Asuna, strive to survive after a killer known as the Black Swordsman appears; the voice cast includes Tomoyo Kurosawa, Koki Uchiyama, Yoshitsugu Matsuoka, and Haruka Tomatsu, with the theme song Reach for the Rainbow performed by Iori and Lara.