Asahi and Mirai went from friends to lovers. The two of them led a peaceful, happy life until one day, Mirai receives nothing more than a message from Asahi saying "Wait for me." At the same time, Earth is under attack from mysterious invaders. Mirai, on the verge of losing his life, is finally reunited with Asahi, but it seems that Asahi has a secret he can't tell anyone...!?