Jessica and Tiffany are both from America. They are twins, but they didn't know until they finally found out the twin necklace their father gave them before their mother abandoned them in the opposite exits of the beach. 

Characters..

Jessica

Abandoned by her mother at the age of 4, found by the Jung family and they adopted them. The Jung had one daughter younger than Sica by 2 years named Krystal. Despite the fact that they are stepsisters, they are very close to each other. Sica love the Jungs until one day someone purposely head towards her stepmother and father using a car and killed them. When the media asked, "What about your stepsister, Krystal?" She will always answer, "Call her my stepsister again and you'll get into trouble. Listen properly, SHE IS MY SISTER, NOT MY STEPSISTER."

Tiffany

Same like Sica, Fany was also abandoned but at the opposite exit of where Sica was placed. Fany was found and adopted by Mr.Hwang who had no children at all after the death of his wife and his daughter, Hwang Yunje. He reallly loved Fany and treated her like a princess since he really miss Yunje who he could always talk to until Fany came to his life and replaced Yunje for him. Fany really loved her stepfather, she once even said to the public, "He is MY FATHER. If my biological parents die or whatever, who cares? I AM NOT their child and I AM Mr. Hwang's second daughter. MY SISTER, Yunje died together with MY MOTHER before I could even see them. Umma, unnie, saranghae."

Krystal

Jessica's stepsister, but they both declared they are SISTERS not STEPSISTERS. Two years younger than Sica, Krystal also entered SMentertainment 2 years after Sica. Krystal never care if her fans are rich or poor, she loves them all the same. She sometimes even held charity bazaars with her sister to help the poor and orphanages.

Note: These are not the only characters, but they are the main characters ^^