Ryu Young Hee (or Ryu Rebecca) is a half American, half Korean teenager, tough on the outside, a almost all the time, an ice queen, hot-tempered, pretty rough but sensitive and loving on the inside. She loves reading, being quite a nerd. Doesn’t have too much patience, yells a lot but this is like her usual way of communicating. Some consider her antisocial but it takes her a long time to trust people and being a difficult person, she doesn’t find friends easily. She doesn’t have too many friends, just a handful of people she knows since she was in diapers. Attends Seoul Academy and wants to get a master’s degree in business administration. She's obsessed with purple.  

Kurokawa Michiko (or Park Min Rin) is Young Hee’s best friend, being the only one who understands, knows and supports her. She’s half Japanese, half Korean, speaks both languages perfectly and English as well. Has a younger sister, Ayumu. Michiko is friendly, calm, quiet and shy. She likes to joke and laughs a lot with Young Hee and her sister. Doesn’t like her height. Attends the same university as her friend, studying art.

Kurokawa Ayumu (or Park Yeon Hyo) is Michiko’s younger sister. Quite evil, likes to get on her sister’s nerves and Young Hee’s as well, but loves them both sincerely. Funny and joyful, has a bubbly personality.

Young Hee has been living on her own for a couple of years. Her parents have always wanted their daughter to have everything she desired so they started a business. They never thought it would be so prosperous but they had luck and they’ve managed to expand it and have been forced to travel a lot overseas. The family gathers only around Christmas or Easter so Young Hee decided to rent an apartment. She even took a job to pay the bills, even if her parents provide her with generous amounts of money. She likes being independent.

Michiko and Ayumu’s situation is not so different. They live by themselves as well. Their mother had the opportunity to run her family business in Japan but the girls, who had grown in South Korea, refused to go with her. They’d only visit her a few times a year. Their father is still in the country, but his job keeps him away from his daughters and doesn’t get the chance to see them often.

Their life isn’t easy but they don’t complain and are always grateful for everything they have.

But everything changes one morning. Their lives won’t be the same because other people start to show up. Some will be beneficial for the girls, but some… Well, some won’t. Their world will be turned upside down by a common phone call.