Young Guk becomes confused after having kissed Dan Dan on the lips, and Dan Dan, who finds it inconceivable that their lips touched, becomes bothered by it. Meanwhile, Dae Ran gets annoyed with Ki Ja and Sa Ra bickering about their circumstances. To cool things down, she gives Young Guk the advice of getting engaged to Sa Ra, and Young Guk thinks about it.

Jealousy overcomes Young Guk after seeing Dan Dan and Hyun Bin affectionately together. Using coincidence as an excuse, he tries to spend as much time with her as he can. Sa Ra attempts to get close to the 22-year-old Young Guk, but it's not as easy as she thought it would, and she becomes irritable. Meanwhile, Young Guk participates in Se Jong's sports day.

Young Guk feels guilty about liking another woman when he is just about to get engaged. He tries to make himself like Sa Ra but finds it tough to get Dan Dan off his mind. Meanwhile, Sa Ra is appalled after learning the newly dispatched diver is Cha Gun and will work at Young Guk's house.

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 finally regains all of his memories but doesn't want Dan Dan to get mixed up in his complicated life anymore. Soo Chul wants to send Dan Dan abroad before she finds out about Young Guk's memories coming back and arranges a meeting between her and Anna. Meanwhile, Sang Gu gets suspicious of Sa Ra's behavior around Se Jong and runs a DNA test.

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.