The unnamed sky once shed a drop of blue tear, fell to the ground, and turned into an elf in search of a name. Elf is outspoken and cute, and has made many good friends. The most important friend, Firefly, spent the best time with her. Unexpectedly, humans destroyed the bond between elves and demons, triggering a black history. The balance of the world has been destroyed. Can the elves complete the task of finding their names and return to the sky? Can we save the world and balance the darkness and light in the world? Everything is still unknown...