Eun Ho writes an e-mail to his father, Hyung Jin, and leaves to find his birth mother. At Jeju airport, Eu Ho tries to take a taxi that Jung Eun gets off in a hurry and sees a box she left. Eun Ho gets on the boat bound for Biyangdo and meets her again. Eun Ho visits Dal Ho, who knows where his mother is. Eun Ho soon finds out Jung Eun is Dal Ho's granddaughter who has lost the will to speak. Eun Ho feels empathy for Jung Eun because she is similar to him and tries to get her to speak again.

Eun Ho starts to have good feelings for Jung Eun, and she also feels good for him. Hyung Jin and Hye Rim come to the jazz bar where Eun Sub plays double bass. Eun Sub turns the car and runs away while being dragged home. Hyung Jin reports the car stolen, and Eun Sub is arrested by the police. Eun Sub is known as Dr. Crybaby at the hospital because he sheds tears whenever he sees blood. Eun Sub hates the doctor's white coat and the smell of the hospital. He feels like vomiting when he sees blood.

Jung Eun keeps shouting at Eun Ho not to leave, and Eun Ho looks at her from the boat that leaves the dock. Jin Tae, who also watches Jung Eun from the boat, drops his jaw. Jin Tae cannot believe to see Jung Eun speaks. Eun Ho leaves after telling her he will be back soon, and Jung Eun runs to the health care center.

Eun Sub is devastated by Eun Ho's accident. Eun Sub seems to hate Eun Ho but, in fact, likes him. Drunk Eun Sub comes to Eun Ho's patient room. Eun Sub tells Eun Ho, who is in a coma, he is just upset with Eun Ho for hiding his Gundam, not hating Eun Ho. Eun Sub gets tired and falls asleep next to Eun Ho. At that time, Jung Eun enters the room and bursts into tears when she sees Eun Ho on his sick bed. Eun Sub sobs while sleeping, and Jung Eun sobs as she wipes his tears.

An emergency arises in the hospital, but when Eun Sub sees bloody patients coming in, he runs away to the rooftop and has a hard time. Jung Eun drags Eun Sub impatiently and says he should not hide when patients like his brother are dying. Eun Sub reluctantly heads to the emergency room and sees a patient vomiting blood in his mouth while he is forced to treat the patient. Eun Sub accurately identifies the patient's condition and saves the patient from an urgent crisis.

Eun Ho wakes up with his memory back to 13 years old. Eun Sub comes to Eun Ho with Jung Eun when hearing that Eun Ho has woken up. Hyung Jin calls Jung Eun and tells her it is up to her whether she stays, and Jung Eun says she will take care of Eun Ho. Eun Ho is discharged from the hospital but refuses to take the car to go home. Eun Ho cries when the scene of a car accident flashes through his mind, and Jung Eun hugs Eun Ho and comforts her like his mom. Eventually, they go home by train.

Eun Sub and Jung Eun meet Min Jung, Eun Ho's friend from elementary school, to help Eun Ho's memory back. Eun Sub introduces Jung Eun to the jazz bar where he plays so she can have a job playing the piano. Jung Eun comes to Eun Ho's home to take him to the hospital, but she cannot find him. Jung Eun and Eun Sub look for Eun Ho everywhere, but Eun Ho is nowhere to be found. Jung Eun hears strange sounds in the attic while waiting at home. When she goes to the attic, she finds Eun Ho crying.

When Jung Eu, Eun Sub, and Eun Ho have dinner together, Jung Eun finds out Eun Ho hates eggs, and she cannot hide her disappointment. When Nam Jin calls Eun Sub and says Jung Eun did not come to play the piano, Eun Sub feels something is wrong and goes to find her. Eun Sub finds Jung Eun collapsing in the bathroom. Dal Ho comes in a hurry from Jeju and convinces Jung Eun to be back and wait at home. Jung Eun tells Eun Sub she will leave, and Eun Sub is disappointed.

Jung Eun goes to the airport to go back home, and Eun Sub comes to the airport to meet her. Eun Sub tells her that Eun Ho is recovering his memory fast. Eun Ho, who misses his mother, asks Hyung Jin about the car accident, but Hyung Jin cannot tell the truth. Min Jung says Jung Eun is Eun Sub's girlfriend, but Eun Ho thinks Jung Eun doesn't seem to be just a caregiver. When Eun Ho tells Jung Eun not to be around him, she is frustrated and ends up telling him what she is not supposed to say.

Eun Ho takes Jung Eun out and asks why Jung Eun has his mother's piano. Jung Eun does not know what to do, but she doesn't say anything. Eun Ho goes to the hospital and asks about the accident, but no one tells him, and he becomes aggressive. When Min Jung hypnotizes Eun Ho as a joke to help him feel better, Eun Ho suddenly remembers packing his bag to go somewhere and goes to Eun Sub. Eun Ho tells Eun Sub that he remembers giving him his car and starts to look for his bag in the car.

Kyung A thanks Eun Sub for taking care of her, and she tells him to come anytime he has nowhere to go. Eun Ho runs into Jung Eun in front of his mother's house. When Eun Ho says to wait for his mother, Jung Eun tells him everything. Eun Ho regrets visiting Dal Ho to find his mother, and Jung Eun is devastated to see him that way. Jung Eun tries to tell Eun Ho about herself, but he refuses to hear. Jung Eun encounters Eun Sub in front of Hye Jin's house. Eun Sub hugs her and says he loves her.

Eun Ho appreciates Jung Eun politely for getting him better. Jung Eun feels uncomfortable and says he was not that formal with her before. Eun Ho says he may refuse to remember the island, the health care center, and even Jung Eun in his subconscious. Eun Ho asks Jung Eun if she can understand him and if they can start like people who meet each other for the first time. Jung Eun accepts with great happiness. Jung Eun is happy, but when she thinks of Eun Sub, she sheds tears for no reason.

Eun Ho tells Min Jung he recovered lost memories and all the memories he lost were about Jung Eun. But Min Jung asks Eun Ho to stay with her for a week. Jung Eun is at the dock to set off her grandfather and is surprised to see Eun Sub. Eun Sub stays at the health care center for a few days. Eun Ho runs into Dal Ho at the hospital and says he will go to the island to meet Jung Eun. Dal Ho tells Eun Ho that Hyung Jin seems to have problems with his heart and asks Eun Ho to stay with his father.

When Kyung A comes home, she finds Eun Sub in her house. Kyung A is happy to see him and tells him she thought he would never come. When Kyung A tells Eun Sub her life story, he feels empathy and hugs her. Eun Ho goes on a date with Jung Eun and proposes to her. Eun Sub says to himself that he will never come back to see Jung Eun while he sees Jung Eun and Eun Ho at a distance. When Eun Ho tells Eun Sub that he will marry Jung Eun, Eun Sub gets angry and says he can never be her brother-in-law.

When Eun Sub brings Kyung A, his family and Jung Eun are puzzled. During the meals, Hye Rim asks Eun Sub who Kyung A is, and he says he will marry her. Hye Rim gets angry and pours ice water on Kyung A. Kyung A cries and yells at Eun Sub that he makes her not want to work at a bar anymore but he also humiliates her. Min Jung comes to Jung Eun and asks if Jung Eun loves Eun Ho. When Jung Eun doesn't answer Min Jung, Min Jung says she won't give up until the day Jung Eun and Eun Ho get married.

Eun Sub calls Eun Ho to tell him he is with Jung Eun. Jung Eun asks Eun Ho to help Eun Sub, who works at a bar. When Eun Ho says he can't live with her unless she lets Eun Sub go, Jung Eun asks if there's no problem between the two without her. Eun Sub says seeing her is painful and wants to see her after many years. When Jung Eun leaves Eun Sub, gang members rush in and beat him badly. Jung Eun tries to protect Eun Sub, but she is also assaulted by them and collapses next to Eun Sub.

Eun Ho asks Jung Eun if she wants to break up with him because of Eun Sub, but Jung Eun says that it is because Eun Ho makes her overwhelmed by giving her too much. Eun Sub asks his mother for money to save Kyung A and says he will do what she wants if she gives him money. When Hyung Jin hears their conversation, he tells Eun Sub not to make a deal with the money. When Eun Ho comes to the piano class to see Jung Eun, Jung Eun shouts at him that she is not his mother.

Eun Sub asks if she does not marry Eun Ho because of him. Eun Sub asks Jung Eun to tell him what she feels, but she doesn't say anything. Eun Sub shouts at Eun Ho that he wants to run away with Jung Eun but cannot do it because she is a woman Eun Ho loves. Eun Ho goes to Jung Eun and tells her he thinks of her as his twin because he loves her. But Jung Eun says she does not love Eun Ho. Eun Ho is frustrated and drinks with Min Jung. Eun Ho gets wasted and spends a night with Min Jung.

Min Jung says she gets hurt because Eun Ho spent a night with her by mistake. Eun Ho says he will get what he deserves later if he has done anything wrong. Hye Rim misunderstands photos of Eun Sub and Jung Eun together and goes to meet Jung Eun. Eun Ho tells Jung Eun what Min Jung lies about, but Jung Eun says nothing will change. Eun Ho keeps asking Jung Eun if she loves Eun Sub, and she eventually admits. Eun Ho tells Eun Sub that Jung Eun loves Eun Sub and urges him not to rush.

Jung Eun calls Eun Sub while waiting for him at the airport. Chul Soo answers her call and says that Eun Sub is in the operating room because Eun Ho is injured. Eun Sub tells Jung Eun that Eun Ho was hurt to save him. After the surgery, Eun Ho asks Eun Sub why he didn't go to the island. Eun Sub says he owes Eun Ho forever and takes good care of Eun Ho. Eun Sub has a happy time with Jung Eun for a while. Eun Ho meets Min Jung and asks if they can have some time since he still misses Jung Eun.