Dan Oh is a high school student. One day, she suddenly realizes that something is going on with her. She suddenly loses her memory and her personality changes. She goes to the doctor, but the doctor says that she is completely normal. However, she now can see into the future! What is going on with her?
Dried Squid Fairy tells Dan Oh that they are in the world of comics. Dan Oh doesn’t want to believe his words, but she realizes that it is true. She thinks her character is the lead character of the comic, but she notices that there is another character who is the female lead of this world.
Dan Oh realizes that her role in the comic book is to make the lead characters fall in love, and she hates it. Even she smashes the plaster casts, it goes back to normal since that is not intended by the writer. Dan Oh asks Dried Squid about the black hole she saw at the library, but Dried Squid says that it’s a dangerous thing.
Dan Oh and Kyung have dinner together with their parents. After the dinner, Dan Oh warns Kyung to keep a distance from her, and Kyung thinks she is odd. One day, Dan Oh really falls down the stair, but someone saves her. Dan Oh wants to find the guy who saved her, but it is not easy.
Dan Oh finally finds the guy she was looking for, but she suddenly teleports to the hospital. Dan Oh meets Do Hwa at the hospital, and Do Hwa tells Dan Oh that she has been acting strange these days. Do Hwa becomes aware of himself, and Dan Oh tells him that he is in the world of comics.
Mu Young asks Dan Oh if she wants to quit school and travel the world with him. Dan Oh tells Mu Young that she wants to go to the summer camp, and he allows her to do that. Dan Oh is excited to go to the summer camp with Number 13, but she can’t find him anywhere at the summer camp.
Dan Oh gets lost in the mountain while the couple night trekking, and she is scared of being alone in the midst of the mountain. At that moment, Number 13 comes to Dan Oh. Dan Oh realizes that the story has changed because of Number 13, and she names him Day since he changed her day.
Dried Squid tells Dan Oh that everything will go wrong when extras get names and start acting on their own. Day gets hurt because of Kyung, and Dan Oh thinks that it is all because of her. Dan Oh doesn’t go to Kyung’s house for dinner, and Kyung takes it out on Dan Oh. At that time, Day appears in front of Dan Oh.
Dan Oh tells Kyung that she wants to break up with him. Also, Dan Oh is determined to change the storyline of the comic, but Dried Squid tries to stop her, saying such a change might destroy the world of the comic. Meanwhile, Nam Ju's parents visit the school and plan out Nam Ju's birthday party.
Nam Ju's birthday party is held. Haru, who is not invited to the party, manages to go into the party in disguise and tries to change the storyboard as he, Dan Oh, and Do Hwa planned. Do Hwa lets Ju Da know about his feelings for her. However, because of Kyung, Haru's plan goes wrong.
Dan Oh tells Kyung that she never liked him. Like Dried Squid said, Haru’s pain gets worse when the story changes. Kyung tells Haru that he is just toying with Dan Oh, and Haru gets mad at his attitude. Meanwhile, Haru decides to be the only person who can change Dan Oh’s fate.
People start to recognize Haru. They remember Haru’s name, and he has his name tag now. Kyung asks Dan Oh out for a date, but he stands her up all of a sudden. Haru appears in front of Dan Oh at that moment and they spend a great time together. Meanwhile, Kyung gets to know the existence of the book, “Secret”.
Kyung tells Dan Oh that he knows about the book “Secret”. Haru disappears all of a sudden, and the students in Seuli High School don’t remember him at all. Dried Squid tells Dan Oh that it is because of her, and Dan Oh doesn’t know what to do. Kyung tries to make Dan Oh feel better, but it’s not easy.
On Seuli High School’s Sports Day, Dan Oh plays a game with Kyung. While playing the game, Dan Oh falls down, and Kyung gets annoyed again. At that moment, Haru appears in front of Dan Oh. Dan Oh is happy to see Haru, but Haru doesn’t seem to remember Dan Oh for some reason.
Haru becomes popular in Seuli High School. Nam Ju announces that Ju Da is the only woman for him from now on. Dan Oh decides to accept her own fate and forget about Haru and her struggles to change the story. Meanwhile, Haru keeps having a dream about Dan Oh.
Ju Da suggests Nam Ju that he should make up with Do Hwa, and Do Hwa is back into A3. Kyung discovers the book “Trumpet Creeper” and finds out that Dan Oh is in the book. Meanwhile, Dan Oh tells Kyung that everything that she does on stage is all just what the writer wants.
Haru returns to his old self, and Dan Oh and Do Hwa are happy to have the old Haru back. Dan Oh is glad to have Haru back, but she is also afraid to lose him again. Meanwhile, Dan Oh and Haru play hooky and they find an antique shop.
Haru continuously feels like something new that he has seen is already familiar to him. Kyung keeps picking a fight with Haru, and Haru doesn’t step back. Dan Oh’s condition gets worse. Meanwhile, Dried Squid realizes that Haru regained his memory back, and he worries about the future.
Kyung finds the book which Dried Squid burnt, and Dried Squid tells Kyung the former work of the writer has nothing to do with their current world. Kyung is mean to Dan Oh on the stage, and he regrets it after the stage. Meanwhile, Kyung tells Haru that he can’t beat him since he is a mere extra.
Haru wants to change Dan Oh’s story. Ju Da waits for Nam Ju, but he doesn’t come. Do Hwa tells Ju Da to think about herself first, and Ju Da tells him there’s nothing she can do on her own. Meanwhile, Dan Oh and Haru make a promise to meet in front of the tree on October 10.
Kyung is worried about Dan Oh because she just left the hospital, and he recalls his old memory with Dan Oh. Dan Oh comes back to school. Dan Oh is happy when she is with Haru, but Kyung isn’t happy to see her like that. Meanwhile, Kyung asks Dan Oh if she likes Haru because he can change the stage.
Nam Ju leaves Seuli High School, and Ju Da tells him that he doesn’t have to worry about her. Dried Squid tells Haru that he needs to stop the person who’ s trying to change the stage even if it’s Dan Oh. Meanwhile, there’s a transfer student in Seuli High School.
Dried Squid tells Kyung that he lost everything because of him. Kyung sees the comic book and tells Dan Oh that she will call of their engagement. Haru tells Dan Oh that they have known each other for a long time. Meanwhile, Ju Hwa suggests Dan Oh that she should get the surgery.
Sae Mi bullies Ju Da again, but Ju Da won’t let her slide this time. Dan Oh sees the storyboard again and decides to change the stage once again. Do Hwa and Haru try hard to change the stage, but it is not easy. However, Haru succeeds in changing the stage. Kyung tells Dan Oh that they can never be apart.
In “Trumpet Creeper”, Haru witnesses Dan Oh’s death. He doesn’t want to admit that the same thing is happening in “Secret”, but Dried Squid tells him that the story is repeating itself. Meanwhile, Dan Oh’s condition gets worse, and she wants to keep it secret from Haru.
Do Hwa gets to know that Ju Da is aware of herself. Jun Hyun warns Haru to leave Kyung alone. Kyung tells Dan Oh that he’ll suffer from a wound that he’ll never recover from if she dies. Haru gets to know that Dan Oh needs surgery, and he is afraid of losing her because of that surgery.
Do Hwa and Haru try to change Dan Oh’s story. Haru goes to the hospital and switches Dan Ohs’ medical chart to another person’s. Dan Oh doesn’t need to have surgery anymore, but Kyung tells Haru that Dan Oh will die because of him. Kyung warns Haru to stop changing the story before he puts Dan Oh in bigger danger.
Dried Squid warns Kyung not to meddle with him and Su Hyang in this world. Dan Oh’s story has changed, but she is still sick in the shadow. Haru gets to see the scene where he kills Dan Oh in “Trumpet Creeper”. Meanwhile, Kyung gets to know that only the self-awareness disappears when someone dies in the shadow.
Dan Oh can’t remember anything that happened in the shadow, and she is not aware of herself now. Everyone in the school gets to know that Nam Ju was born out of wedlock, and they start to ignore him. However, Ju Da stays by his side even in the shadow. Meanwhile, Su Hyang is aware of herself.
Dan Oh and Kyung promise to meet at the school to celebrate their 10th anniversary. However, Kyung tells Haru to go meet Dan Oh in place of him, and Dan Oh gets to find her memory back there. Dan Oh and Haru spend a great time together again, but Haru finds out that he has no name in his nametag.
Haru wants to do everything for Dan Oh. Do Hwa realizes that the real Dan Oh is back, and he is happy to have his friend back. Dried Squid suggests Haru and Kyung that they should all forgive each other. Meanwhile, Jun Hyun tells Haru that he is envious of his bravery to change his own fate.
Haru’s scar on his hand disappears, and he realizes that it’s time to be erased from the comic book. After Haru’s disappearance, Dan Oh still misses Haru. Even on the graduation day, Dan Oh thinks about Haru. Meanwhile, she discovers a diary near the 300-year-old tree, and she finds out Haru’s drawings.
