In the future…Yu Mi’s inner cells tour her library. There is one book for each year of her life. One young cells asks her most embarrassing event. The librarian shares it happened when Yu Mi was 32 years old…
Taken aback at her ex-boyfriend’s impending marriage, Kim Yu Mi (Kim Go Eun) lies that she’s getting married too. Yu Mi provides details about the upcoming ceremony abroad. Gu Woong (Ahn Bo Hyun) walks up. Yu Mi is aghast knowing he’s overheard her lies about their upcoming marriage. Her ex-boyfriend introduces himself to Gu Woong as a college friend. Gu Woong is friendly in return. Her ex-boyfriend congratulates him on the upcoming wedding. Gu Woong looks are Yu Mi’s lowered head. Her inner cells can’t believe the situation and are collectively horrified. Gu Woong thanks her ex-boyfriend on his warm wishes for their upcoming marriage. Yu Mi looks at Gu Woong in shock. He gives her a gentle smile. When the ex-boyfriend presses for details about their Hawaiian wedding, Gu Woong declares they head back into the church or they’ll miss the ceremony.
After the wedding, rumors won’t die that Yu Mi and Gu Woong are getting married next year. Chae Ugi, Yu Mi’s co-worker in sales 5 years her junior, presses Gu Woong about the wedding. Gu Woong’s co-worker Sae Yi (who wants Gu Woong for herself) is all ears. Gu Woong refuges to confirm or deny the rumor. He tells Chae Ugi to talk to Yu Mi.
Back at work, Chae Ugi asks Yu Mi if the rumors are true and she’s marrying Gu Woong. She denies it.
Gu Woong’s co-worker Louis demands to know if the rumor is true.
The librarian cell states the sensitivity cell was put on trial for going rouge when talking to the ex-boyfriend. She was sentenced to solitary confinement for 1 month.
Gu Woong’s inner cells see the sea churn as his inner desire to marry tries to free itself.
The librarian tells the cells even more happened…
Yu Mi tells Gu Woong she’s going to start training for a marathon and may not have as much time to spend with him.
Sae Yi reads Yu Mi’s social media and doesn’t like what she sees. Sae Yi’s inner bulletin board reads if I marry, it will probably be Gu Woong.
Gu Woong is surprised when Sae Yi stops by his apartment to borrow a hammer. She announces she moved into the building last week. She ropes him into helping her put up a clock.
Gu Woong is late to a date with Yu Mi because he helped Sae Yi. He decides not to tells Yu Mi.
The librarian tells the cells even more happened…
Yu Mi doesn’t notice other good looking men. Her inner cells declares the men reconnaissance team isn’t working and on vacation with Gu Woong in the picture. She goes over to Gu Woong’s apartment and they order take out. Yu Mi shows him the couples shirts she purchased. they decide to make love before food.
After Gu Woong leaves, Yu Mi goes for a run. She meets a coworker in the park. He mentions he found her umbrella. She’s thrilled. She finally notices he’s good looking. She tells him she’ll come to the marketing department to retrieve the umbrella. The coworker Yu Babi (Jin Young) smiles and says he’ll leave it at the front desk.
The next day, Yu Mi picks up her umbrella at the front desk. Her co-worker, Yi Da, can’t believe that the good looking transfer from Jeju Yu Babi is the one that returned the umbrella. Yu Mi says he lives in the neighborhood.
Yu Mi goes for a run. She sees Yu Babi in the park. She explains she trains when her boyfriend is busy. Yu Babi shares his girlfriend is a reporter and often busy too. He suggests she workout early to avoid the crowds. They wish each other well and go their respective ways. Her inner cells wonder if Yu Babi might be interested in Yu Mi.
They meet again in the park. He compliments her. She notices him. Yu Mi’s inner cells go on alert. She asks what he said. He asks if she likes his outfit. She does. He likes her hair. He leaves. Yu Mi watches. The inner cells decide to think about Yu Babi’s actions as if he were a girlfriend. They calm down. The reason cells declares they should also think about Sae Yi’s actions as if she were a boyfriend. They still don’t like Sae Yi’s actions.
Yu Mi and Gu Woong chat. She admits she’s conservative when it comes to men and women having friendships. Gu Woong apologizes that he’ll have to work again this weekend. He promises to be done with the overtime during the month.
Yu Mi goes shopping. She runs into Yu Babi while he grocery shops. He admits he is making dinner for his girlfriend. She gives him a recipe for tarter sauce. He takes a call from his girlfriend. She breaks their date. Yu Babi explains the situation. He admits dating a busy person can be lonely. Yu Mi knows how he feels.
As she lays in bed, she misses Gu Woong. He texts her as he heads home. She decides to surprise Gu Woong and head to his place. Her inner cells love the idea. She texts Gu Woong to sleep well. She gets out of bed. She packs clothes for the next day at work. She takes a taxi to Gu Woong’s building.
She’s all smiles as she enters the lobby and gets on the elevator. She’s taken aback when Sae Yi is at the 5th floor. Her inner cells go on alert. Yu Mi asks Sae Yi why she’s in the building. Sae Yi acts surprised that Gu Woong didn’t tell her she lives in the building now. Yu Mi can’t believe it. Sae Yi explains she’s heading to Gu Woong’s apartment to borrow something. Yu Mi’s sensitivity cells breaks out of solitary. The dark clouds gather. Sae Yi rings Gu Woong’s doorbell. He’s taken aback to see Yu Mi behind Sae Yi. Ever helpful, Sae Yi explains Yu Mi didn’t know she lives in the building now. She takes the wine glasses Gu Woong offers, smiles, and turns to leave. To rub salt in the wound Sae Yi tells Yu Mi she’ll invite her to a housewarming party. Yu Mi smiles and says to invite her. Sae Yi wishes them good night and leaves.
Gu Woong invites Yu Mi inside. She stands there before she enters. The storm rages inside. Yu Mi’s sensitivity cell rails that she trusted Gu Woong. Yu Mi looks at him with accusation in her eyes.
Trust can be tenuous. This episode Yu Mi was oblivious to other men until she saw coworker Yu Babi (Jin Young). They are both in relationships where their partner is busy leaving them alone. That’s common ground. Gu Woong lied by omission when he didn’t tell her Sae Yi moved into the building. Sae Yi sported a look of glee and triumph when she left Gu Woon’s apartment with Yu Mi fuming.
Kim Yu Mi (Kim Go Eun) didn’t notice other men…until she did. Yu Mi told Gu Woong she’d be training. He told her he’d be working overtime until the launch of the game. That left their time together limited. That opened the door for Yu Mi to notice Yu Babi. Not romantically but as a good looking man.
Gu Woong (Ahn Bo Hyun) kept Sae Yi’s apartment location a secret. Gu Woong’s diversion from trying on a couples shirt to making love was darling. Yu Mi fell in readily. He almost told Yu Mi when Sae Yi moved into his building but he didn’t want to deal with the fallout. Bad choice, now the fallout will be worse because he lied by omission.
The sixth song of the OST is a delight called “My Day” sung by J.Una.
I rank this episode as almost terrific, 8.5 on a 10-point scale.