Lindi Shen is an SM trainee going on three years after moving to Korea from her home in the United States. She's learned Korean and can speak it fluently, and she's already become close friends with her sunbaes in Girls' Generation, Super Junior, and SHINee. Even at the worst times, she can count on her best friends Onew and Jonghyun to be there for her, but as long as she can remember, she's been in love with Onew and will do anything, even hide her feelings, just to keep his friendship. Jonghyun is the only one that is aware of her feelings.

Lee Jinki, or Onew, is Lindi's sunbae and Oppa in the famous group SHINee. He's always there for her and cares about her deeply.

Kim Jonghyun is like an older brother to Lindi and he is her closest Oppa. He always has her in mind and would take a bullet for her.

Lee Jiyoung was a trainee with Lindi. They were roommates and the closest of friends until the day that Lindi debuted and she did not. Jiyoung holds a deep grudge against Lindi and will do anything to steal her spotlight and anything that she cares about even if it means going after the one she loves.

Park Joo-yeon was the third roommate with Jiyoung and Lindi. She is the only one aware of Jiyoung's hate towards Lindi, but because she is in the famous group Red Diamonds and an Unnie to Jiyoung, she keeps shut. Even though, Lindi is a good friend, she feels that she cannot do anything.

Ahn MinYoung, Lee Eunmi, Park Young-ju, and Choi Hana are the fellow members of the Romantics alongside Lindi. EunMi is their leader, and MinYoung is their maknae. The girls are very close.