At age 17, Yi Jing is thrown off a building and brutally murdered. Just before she dies she calls her sister and asks her to save her. Yi Zhen runs to the building but is delayed when she is thrown into the pool, and, having a morbid fear of water, cannot save herself. Just who holds the secret and what is it? What is the website Dark Heart (黑暗之心) really about? If Bandage is Ke Jie and Rock Barbie is Yi Jing, just who is the DarkLord? Who is Sade, Chucky, and BabyXun?
Yi Zhen was previously sexually harassed by Ren You, who was a teacher in the school. Although the teacher was subsequently fired, he continues to stalk and video her. He believes that he is innocent but what are his real intentions?
Yi Jing is continually stalked by Ke Jie and they soon become friends in their solitude. What is his big secret that leads him to take his own life?
Ke Qiang and Yi Zhen are drawn together to investigate just how their siblings die. As more clues come to the surface, the truth is slowly revealed. Things are never quite as they seem...
The principal's elder 18 year old twin daughter; Yi Zhen (recognised by her long hair) is the more extroverted sister and stands up for herself as well as her sister, taking injustice personally. Yi Zhen has a phobia of water which stems from her memories of her throwing her sister (and consequently falling in herself) into a swimming pool when they were 6. She hangs out after class with Jia Wei. She wants to appear perfect to everyone, but this is something only her sister knows.
The GTV website states: Xu Yi Zhen (older sister) described as: 17 years older, high school senior From outward appearance, I am perceived by others as smart, good personality, pretty, and cute, but not an ounce of arrogance. It's true, I am the perfect model that people envy and get jealous over, but I adore all the attention I get, and I love the fake self I have created for myself. To become number 1, I would stay up late study and not care about my health. Yes, you can call me the "Queen of Fakeness" because I care about how people think of me. People's adorations and praises gives me the strength to live. The only person that knows about my fake outward appearance is my younger sister. But in private, I am lazy and obstinate. I am so unlike my younger sister, she is so gentle, sweet, and patient (I think it's probably due to her poor health). I have never seen her angry at anyone.
The principal's younger 18 year old twin daughter; Yi Jing (recognised by her short hair) suffers from severe asthma and is always coddled by her mother and sister. She is more reserved and innocent and hangs out after class with another female student, shopping or eating. Due to her sickness she skipped a year of school. She never gets angry and appears to be compassionate and helpful.
The GTV website states:
Xu Yi Jing(younger sister): Compared to my sister, I should be considered as the extra one. It is fate that the day I am born as a twin, people will compare my sister and I with everything. Until I found out my sister's true self, it's true, I was jealous of her. So I've decided to play the role of the gentle, sweet, and cute sister to please my parents. Throughout all this time, YiZhen and I played our roles accordingly, neither of us ever thought about changing anything. But, since I have poor health, I was away from school for one year, during that time, I begin to change.
Many people are angry at the sisters for their apparent aloofness; no guys in the school stand a chance with them.
A friend of the family's; 18 year old Jia Wei is Yi Zhen's best friend from childhood and later boyfriend, who Yi Jing also has a crush on. He is the all rounded 'nice guy' and class president, always helping his underclassmen and listening to his mother, who is a TV presenter. He later passionately investigates the murder, longing to protect Yi Zhen.
Having graduated from high school, 21 year old Ke Qiang makes a living selling pirated CDs on the Internet. He seems to run into Yi Zhen a lot and saves her life more than once. He used to terrorise people in high school and considers himself quite the Casanova. He has divorced parents and his father is in jail for drugs, thus he often plays the father figure to his little brother, Ke Jie.
Ke Qiang's 17 year old younger brother and in the same class as Yi Jing, he is weak and bullied by the others in his school. He is not academically intelligent and has been withdrawn from many schools, to the consternation of his elder brother. He models himself after Ke Qiang but pressure caused him to commit suicide.
Currently the English teacher at the school, 25 year old Yu Wen she used to have an intimate relationship with Ren You.
Previously a Science teacher at the school, 32 year old Ren You was fired when he was caught by students attempting to sexually harass Yi Zhen.
Ke Qiang's friend and business partner, 21 year old Ye Jia is secretly in love with Ke Qiang but can't bring herself to tell him.
17 year old Ai Ling is Yi Jing's best friend and seatmate, she too has dark secrets.
The twins' mother; 43 year old principal of the school.
Jia Wei's mother and 45 year old famous news presenter; her husband died when Jia Wei was little - he was Zhong Xuan's business partner.
The class bully, his first screen time is when he beats and humiliates Ke Jie for trying to 'get' Yi Jing when no one else can.