"She who is afraid of water, what kind of love song will she compose when she meets him who is wandering in the sea?" One day, Areum received a phone call saying that she had a younger brother who was adopted to France? That man is also a world-renowned diving expert! What exactly is going on?

Yoo-i is a very special girl -- she's like refreshing and fragrant orange bubble gums... A boy appears all of a sudden and becomes a natural part of her life, as natural as breathing air... His name is Joo-in. He says, "Do you know nuna? Nuna is.. my past, my present, and my future... You are like this ladder connecting me to this world..." (Source: Wataame Shoujo)