Anna witnesses Young Guk and Dan Dan sharing a tender moment outside of his office. She tells Young Guk off, saying he should consider what people might say. Young Guk feels confused and hurt by Anna's reaction. Meanwhile, Soo Chul is adamant that Dan Dan break up with Young Guk, even though Yeon Sil tries to talk him out of it.

Dan Dan realizes that Anna is her birth mom and that Soo Chul tried to send her to the US while knowing this fact. Feeling shocked and hurt, Dan Dan storms out of the house. Meanwhile, Sa Ra is taken by surprise when Gun takes her to his humble family home. After turning him down, she goes back to Young Guk's house, using the flowers as an excuse once again.

Young Guk tells the news to Anna. Unlike his thoughts, Anna does not understand their relationship. She strongly claims that the two dating is not right. Moreover, Dan Dan’s father finds out about this as well. As a parent, he cannot accept his daughter going out with a much older guy who already has three children. The future of Young Guk and Dan Dan’s relationship seems darker than ever.

Dan Dan and Young Guk decide to tell the kids about Dan Dan's departure. The kids are sad to hear the news, but they try their best to be mature about it. They say goodbye with a farewell trip and a promise to see each other again in three years' time. Meanwhile, Yeon Sil tails Soo Chul when she figures out something suspicious is going on between him and Anna.

Dan Dan thinks Sa Ra might be lying about her baby being Young Guk's child. She goes to talk to Young Guk, but he refuses to listen. Still, Young Guk spends night after night drinking, and Se Jong's separation anxiety gets worse. Jae Ni decides to take Se Jong to Dan Dan's house. When Sa Ra finds out, they get into a fight.

Young Guk gets a flashback of being with Sa Ra as his 22-year-old self. He confronts her about her lies and demands that she move out. However, Sa Ra refuses to budge. Meanwhile, Dan Dan has a hard time letting Young Guk go, and it's made harder by Se Chan and Se Jong wanting to stay with her. But when Sa Ra shows up at her family home, Dan Dan makes up her mind.

Young Guk's kids receive a great shock when they find out about Young Guk and Sa Ra's engagement. Se Chan even leaves a note saying he refuses to accept Sa Ra as his new mom and disappears. Meanwhile, Sa Ra asks Dan Dan to help persuade the kids about her engagement to Young Guk. Although it hurts her to say it, Dan Dan talks to Jae Ni and Se Chan to support their dad.

Young Guk regains his memories, throwing Sa Ra and Dae Ran into a frenzy. Dae Ran begs Sa Ra not to tell Young Guk about her involvement in their scheme, but Sa Ra declares she will not give up on marrying Young Guk. Meanwhile, Se Chan and Se Jong decide that they would rather have Dan Dan as their new mom than Sa Ra. They start to play Cupid between Young Guk and Dan Dan.

Anna goes to Yeon Sil and asks her to persuade Soo Chul to come and work in the US with her. After hearing the salary Soo Chul would get if he took the offer, Yeon Sil pushes Soo Chul to accept. Meanwhile, the conflict between Young Guk's kids and Sa Ra worsens. Dan Dan decides not to hold her feelings back and to stay by Young Guk's side.

Young Guk recalls a fragment of a memory from when he thought he was 22 years old and becomes anxious that he might have mistreated Sa Ra. Dae Bum and Se Ryeon run into each other and rekindle their love. Yeon Sil gets worked up about their relationship but changes her tune once she hears about Se Ryeon's shares. Meanwhile, Sa Ra continues to feel nauseous and takes a pregnancy test.

Young Guk insists that he and Dan Dan maintain a professional relationship only. However, his feelings for Dan Dan keep showing inadvertently, and Dan Dan wants him to admit he still has feelings for her. Meanwhile, Dae Bum and Se Ryeon's relationship is tested when the two realize they might not be able to bridge the gap between their two very different worlds.

Sa Ra barges into Young Guk's house and announces that she is pregnant with Young Guk's child. Young Guk feels confused about it all but ends up letting her move back in when she shows up with all of her belongings. Meanwhile, Dan Dan is in great shock and moves out. Finally, Dae Bum and Se Ryeon have their wedding.

Dan Dan returns home alone after waiting to meet Young Guk. She is shocked to hear that he is still not back from his hiking trip. Young Guk's family and friends call the police and desperately search for him, but Dae Ran imagines making Se Ryeon the acting chairman if Young Guk isn't found soon. Later on, Young Guk comes home but in a shocking state.

Soo Chul stays with Anna on the day of her surgery and comforts her. When she begins to show her affection for him, Soo Chul feels conflicted. Meanwhile, Sa Ra releases an article about her engagement with Young Guk. Although Young Guk accepts the fact that he must acknowledge the engagement as well, he is upset and ends up spilling his true feelings to Dan Dan in a drunken state.

As Dan Dan keeps trying to make Young Guk admit his feelings for her once again, Young Guk continues to ignore her efforts. Meanwhile, Soo Chul's suspicions for Anna grow to the point that he decides to secretly run a DNA test on Anna and Dan Dan. After discovering Anna's identity, Soo Chul flies into a rage and tells her to stay away.

Young Guk thinks that he hurt Sa Ra by cheating on her with a younger woman, so he wants to make it up to her. He plans a big proposal at the vacation home and takes her there. Meanwhile, Dan Dan becomes saddened when she hears about Young Guk's proposal plans. She makes up her mind to go to the States with Anna.

Young Guk continues to get bits and pieces of his memory back. He wonders why those memories include Dan Dan and asks her about it, but Dan Dan refuses to admit that there was ever anything between them. Meanwhile, Sa Ra grows more anxious as Young Guk seems close to regaining all of his memories. She decides to do something before he does.

Dan Dan finds out that her birth mother is alive. She asks Soo Chul to tell her about her birth mom, but he refuses to do so. Dan Dan decides to ask Anna for help since her birth mom is said to have gone to the US. Soo Chul tells Anna that she must leave as soon as possible. Meanwhile, Young Guk promises Dan Dan that he will help her find her birth mom.

Young Guk finally asks Dan Dan to officially be his girlfriend. Although they are overwhelmed with joy, they’re still nervous about how to tell the news to the people around them. Meanwhile, Ms. Wang goes over to Dae Bum’s family and makes a scene. She claims that they are scheming to steal Se Ryeon’s shares of the company. If she finds out about Young Guk and Dan Dan, the situation will only get worse.

Dan Dan goes to see Se Jong who is suffering from separation anxiety. He gets better as soon as she reassures him and everyone is relieved. However, Soo Chul becomes furious at Young Guk for calling Dan Dan out in the middle of the night and spews harsh words at him. Meanwhile, Dan Dan goes to Anna's apartment while preparing for a fashion show and stumbles upon a photo album.

Se Chan and Se Jong get excited to see Dan Dan back at their house for a job interview, but Young Guk turns her away. Soo Chul tells Anna that she must get surgery and go on living for Dan Dan's sake and decides to stay by her side throughout her treatment. Meanwhile, Mi Sook finds out that Jun O and Mi Rim have been living together.

Se Ryeon hears about the rumor that Seung Ho has a child and asks Dae Ran if it's true. Then, Mi Sook tells Se Ryeon the truth about Seung Ho and that Dae Ran asked to have her set up with him. The truth shocks Se Ryeon to the point where she decides to give it all up. Meanwhile, Young Guk finds himself leaning on Dan Dan more and more, especially when life gets hard.

Young Guk finally realizes that he was wrong to break Dan Dan's heart and tries to win her back. As Mi Sook continues seething over Jun O and Mi Rim's relationship, Jun O declares that he won't see Mi Sook anymore until she apologizes to Mi Rim. Meanwhile, Yeon Sil sees Soo Chul and Anna together and accuses them of having an affair.

Dan Dan grows up being told that her birth mom is dead but still becomes a hard-working young woman. One morning, she overhears her stepmom and stepbrother talking about something that sounds like trouble for the family. Meanwhile, Young Guk is a single father of three kids after losing his wife two years ago. He asks a friend to help him find a live-in tutor.

Sa Ra and Dae Ran decide to lie to Young Guk and tell him that he and Sa Ra were engaged to be married. As Young Guk feels confused, Dan Dan thinks he was two-timing her. She decides to quit her job and tells the children goodbye. However, a small part of Young Guk's memory comes back, making Sa Ra more anxious than ever.