Pandora’s biggest mistake – She shouldn’t have known that such a dangerous object like “Pandora’s box” exists in this world.
Seo Jin starts to fall in love with Ha Na. He is worried about her and he becomes jealous on Robin and Tae Joo. He finds out Robin’s phone password and read his messages with Ha Na.
Ha Na is cold and she is sneezing so Seo Jin shared his blanket with her. She looks into his eyes and thinking that she is in front of Robin she confesses her feelings.
Ha Na:”I like you!”
Embarrassed Ha Na runs away. She can’t believe what she just said. The same time Seo Jin can’t move. He is shocked by Ha Na’s confession and his heart is beating fast. In the morning Ha Na in still embarrassed, but she feels worse when she finds out that Robin left in the morning. She feels that Robin left because he doesn’t want to face her and reject her.
Detective Na calls Tae Joo. They’ve identified the attacker, but the attacker was with Tae Joo the moment detective Na called. He realizes that he’s been caught so he attacks Tae Joo and runs away. Hurt Tae Joo calls detective Na to announce that the attacker run away.
Before attacking Tae Joo the attacker said that he can’t forgive that man because even if that man forgotten everything all he has is his memory. So the man that the attacker was mentioning is Seo Jin and this means that the attacker wants to hurt Seo Jin because of something that happened in the past and Ha Na is just a casual victim.
The attacker is going towards the amusement park so detective Na tries to call Ha Na, but she doesn’t answer her phone. Because he can’t get in touch with Ha Na detective Na calls secretary Kwon, who was with Seo Jin. Secretary Kwan also tries to call Ha Na, but she isn’t answering. When secretary Kwon found out that Ha Na is rehearsing from her friend, Seo Jin just run out. Worried Seo Jin goes to the rehearsing stage while calling Ha Na, but still no answer. The man who love only himself and cares only for himself is now more worried about another person, about Ha Na. Seo Jin found Ha Na practicing and took her home.
Arrived home Ha Na goes to her room to begin packing. Since the police know who the attacker is then she can leave the next day. In his room Seo Jin hear a noise and runs to Ha Na’s room. She fell of a chair while trying to get her suitcase. So she won’t fell again Seo Jin helps her and gets her suitcase. They are awkward with each other and to pass the awkwardness Seo Jin opens the window. The sketches that Robin drew for Ha Na flew on the window. Angry at Seo Jin, Ha Na runs out to pick the drawings. Seo Jin follows her and helps her pick the sketches. He is starting to open up towards her.
While Ha Na was arranging the sketches, back in her room, she tells Seo Jin to not mention Robin in front of her that she will do the same. Hearing that, Seo Jin leaves smiling form Ha Na’s room.
Seo Jin is in his room getting ready to sleep. Suddenly Robin received a message. Seo Jin is curious what Ha Na had to say to Robin and tries various tricks to find out Robin’s password. He found Robin’s password and read the texts Ha Na sent to Robin. She was asking him to forget that she confessed her feelings and to act comfortable around her when they will meet again. From her room Ha Na saw that Robin has seen the texts and she is waiting for his reply, but the reply never came. Seo Jin deleted Ha Na’s texts for Robin.
When he woke up Robin calls secretary Kwon to see what happened after the accident, he fainted after taking Ha Na to the hospital. Just to hear that Seo Jin, with his frozen face had to pretend that is Robin and try to imitate Robin’s smile, made Robin happy.
In her room Ha Na is upset that Robin is avoiding her. Suddenly a text came. It’s Robin and he called her out. She runs excited even if she was saying earlier that she will not give another chance to Robin. But when they met Robin is acting as usual. He doesn’t know that Ha Na confessed her feelings or that Seo Jin deleted his texts.
In the morning Seo Jin is taking Ha Na to the police station to identify the attacker. She is sick and Seo Jin is giving her medicine.
The attacker is in the interrogation room. He doesn’t see Ha Na , but he knows that she is in the other room indentifying him. Tae Joo and Seo Jin are with Ha Na. She is nervous and scared. She identifies him, the man she is seeing in the interrogation room is the man that tried to kill her. After she recognized him, that man comes towards the window. Ha Na is scared and screaming. Tae Joo covers her eyes and takes her out of there. Seo Jin lifted his hand and tries to ask Ha Na if she is alright, but he is too late. Tae Joo took Ha Na out.
Coming out on the hallway, after he was scolded for being ill-mannered with Ha Na by detective Na, Seo Jin noticed that Ha Na and Tae Joo are talking for a long time. He is jealous!
In the car, on their way back, Seo Jin told secretary Kwon to find a good therapist for Ha Na, other than Tae Joo. Seo Joo doesn’t like Tae Joo, he is too friendly with Ha Na.
Arrived at the theme park, Ha Na received a phone call from Ryu Seung Yeon’s secretary to come to his office. Ha Na goes to director Ryu’s office, but soon after her, Seo Jin entered too.
Seo Jin:” What business do you have with my girl?”
Seo Jin dragged Ha Na out and when she asked him why is she his girl, Seo Jin wanted to say that she is his girl since the night she confessed her feelings, but he didn’t. He warned her that Ryu Seung Yeon is just using her to get information about him.
Seo Jin was kidnapped when he was little. To be able to surpass the pain from that experience Seo Jin’s mind created Robin, an alter ego who didn’t went through that painful experience.
When he woke up, Robin received a phone call from Woo Jong and went to see her. From Woo Jung, Robin found out that Ha Na confessed her feelings for him, but he rejected her by disappearing and leaving a message behind.
Robin looks for Ha Na. When he found her, he apologized for not remembering. But Ha Na doesn’t believe Robin’s excuses. In Ha Na’s eyes Robin is pretending to not remember and even if he really forgot that she confessed he should have at least answered her texts. Robin doesn’t understand what texts is Ha Na talking about and checks his phone, but there is no message related to Ha Na’s feelings. Ha Na thinks that Robin doesn’t feel the same way as she is and that is why he pretends to not remember and he also deleted the texts she sent him.
Angry, Robin leaves a message for Seo Jin.