Kim Hyun Joong:

Na Eun best friends since childhood. His family migrated to the United States.  He gave Na Eun a bottle with lavender promising to comeback after 11 eleven years when the lavender season starts. He kept his promise and came back as a successful singer. Stage name is ART.

Kim Na Eun:

A girl who inherited chronic heart disease from her father. Due to the her underdeveloped arteries, she could not undergoes heart transplant. It is dangerous for her to do vigorous activites. Though she grows up normally, her body will become weaker as she gets older, eventually dying.

Kim Na Na:

Na Eun elder sister and has the exact same condition as Na Eun.

Kim Kyu Jong:

Good friend and colleague of Kim Na Eun. He had always love her.

Tiffany:

Kim Hyun Joong ex-girlfriend. She's from America too.

And more casts to come as we proceed with the stories.(;