In episode 18 of Wonderful Days, the family finds out that Dong Hui told Dong Joo and Dong Won the truth. After discovering that Dong Won is his younger cousin and not his uncle, Kang Mool starts paying back all the things that Dong Won did to him before.
Dong Tak calls Dong Seok and tells him that Hae Won disappeared from their house.
After sending Dong Joo and Dong Won home, Dong Hui went to drink with his friend Gook Soo. Suddenly, Dong Hui sees Hae Won walking. He follows her.
Hae Won broke the mirror of a car and told the owner that the person who broke it was Oh Chi Soo driver. When that man calls Oh Chi Soo’s driver, Hae Won gets into Oh Chi Soo’s car. She plans to die with him that night.
Dong Hui stops Hae Won from driving and gets her out of the car. While they argue, Dong Seok came. He tells Dong Hui to let Hae Won go.
Dong Seok :” Is this the revenge you wanted? I knew you weren’t smart, but I didn’t know you’re this dumb!”
After screaming at Hae Won, Dong Seok goes home.
Left alone with Hae Won, Dong Hui is curious about what revenge was his brother talking about. Since Hae Won isn’t telling him anything and Seung Hun is looking for her, Dong Hui takes Hae Won to the police station. Then he goes home.
From outside the gate, Dong Hui hears Young Chun scolding So Shim and Dong Tak. She was telling them that they do not care for Dong Hui. How can they be so worried about Hae Won and not say a word about Dong Hui who hasn’t been home in a few days.
Hearing that Dong Hui enters and acting like nothing happened he asks for food.
Dong Hui:” I’m hungry. Get me some food.”
Dong Hui is eating. So Shim takes a bottle of soju, sits at the table and asks Young Chun to sit next to them. Then So Shim asks Dong Hui since when did he k new that she wasn’t his real mother.
Kang Dong Hui knew that So Shim isn’t his real mother since he was in 7th grade when he went to his friend’s house and heard his friend’s parents talking.
Then So Shim asks Dong Hui how many times she hit him while he was growing up. Since Dong Hui said that she never hit him, So Shim gets up, goes next to Dong Hui and starts hitting him for screaming at his grandfather, for screaming at Dong Ok and because he left without saying anything for few days.
Next morning the Kang family is having breakfast. Dong Hui puts some food into Dong Joo’s plate. She is still mad and cold towards Dong Hui.
Dong Joo:” Dong Won, tell Mr. Kang Dong Hui to stop acting like we’re friends.”
Dong Won takes the food from Dong Joo’s plate and tells Dong Hui to not be hurt by Dong Joo’s words.
Dong Won:” Don’t let her hurt your feelings. Just ignore her, dad.”
Hearing Dong Won calling Dong Hui “dad”, the whole family is surprised. The happiest one that Dong Won is Dong Hui’s son is Mool. Now he can get back on Dong Won for all.
Mool:” Let’s sort out the family tree here. Dong Won and Dong Joo are uncle Dong Hui’s kids, so they’re my cousins! Right, dad?”
The children are leaving for school. Dong Won went ahead to get away from Mool.
Mool and Dong Won meet on the street. Dong Won is apologizing to Mul for how he treated him when he thought that Mool was his nephew. But Mool doesn’t accept Dong Won’s apology.
Dong Won:” If I knew you were my cousin, I wouldn’t have acted like that! Let’s just start all over from scratch, and try to get along as cousins.”
Mool:” Forget it! I’ll make your life miserable! So you better prepare yourself, Kang Dong Won!”
While the two boys talk, Dong Joo came. She tells Mool that since she didn’t accept Dong Hui as her father, she also can’t accept him as her older cousin.
Dong Joo:” I can’t accept Mr. Kang Dong Hui as my dad. So I can’t accept you as my cousin, either.”
But Mool’s reaction to Dong Joo being his younger cousin is different the it was with Dong Won.
Mool:” Fine. Let’s be cousins when you’re ready. Take your time, my pretty Dong Joo.”
Is Mool really that understanding or he just wants to get back at Dong Joo later when he finishes with Dong Won?
Worried that Woo Jin might report Dong Hui to the police for hitting him, Dong Ok goes to see Min Woo Jin. Dong Ok brought lunch. She hides when she saw Woo Jin with Ma Ri.
When Ma Ri left, Woo Jin saw Dong Ok hiding and went to her. They have fun while eating the lunch that Dong Ok brought.
In front of the school, Ma Ri meets Gook Soo. He came to bring his nephew to school. They recognize each other. At first Gook Soo didn’t know that Ma Ri is the girl that he and Dong Hui are looking for, but when he remember the photo with Ma Ri he realize it. Ma Ri doesn’t know at first that Gook Soo is Dong Hui’s friend, but when Gook Soo nephew talk about Dong Won and Dong Joo she asks Gook Soo what are the last 4 digits of his phone number. Then Ma Ri realizes that Gook Soo’s number is the same phone number that was on the poster that the guy who she hit posted it.
Knowing that Gook Soo is Dong Hui’s friend, Ma Ri asks Gook Soo to put in a good word for her to Dong Hui.
Dong Seok called Oh Chi Soo at the prosecutor office. While they are waiting for Oh Chi Soo, Dong Seok asks Mr Park if he has Oh Chi Soo’s phone number. Mr. Park said that he doesn’t have Mr. Oh’s personal number.
When Oh Chi Soo arrived at the prosecutor office, Dong Seok pretends that he doesn’t find a file. Mr. Park gets up from his desk and looks for the file. Dong Seok goes to Mr. Park’s desk, takes his phone and calls someone.
Suddenly Oh Chi Soo’s phone rings. Mr Park has lied. He had Oh Chi Soo number. Dong Seok found out that his coworker, Mr. Park, betrayed him for money. Dong Seok found out that Mr. Park was working for Oh Chi Soo.
Because Oh Chi Soo asked for evidence, Dong Seok told Soo Young to bring Mr. Park’s and Oh Chi Soo’s phone record and also to bring the file that he has and proves that Mr Park got money from Oh Chi Soo.
Seung Hun and Hae Won are meeting. He has been looking for Hae Won since the night that he heard the conversation between Hae Won and his father.
On the other hand, Hae Won is cold towards Seung Hun. She wants to break up with Seung Hun for good.
When Hae Won left, Seung Hun called his attorney. He wants to start a fight against his family.
Eating with Jo Won, Dong Tak finds out from this one that Hae Joo is having a blind date with a man that was married 3 times, but is rich. He gets mad and goes to get Hae Joo.
Cha Hae Joo is angry that Dong Tak ruined her blind date. Dong Tak grabs her and tells her that he knows that she likes him.
Dong Tak:”Didn’t you like me? Didn’t you have a crush on me, Cha Hae Joo? You thought I didn’t know that?”
The same time, Dong Seok is interrogating Hae Won.
During interrogation, Dong Seok proposes to Hae Won.
Dong Seok:” If I asked you to marry me…will you say yes?”
What will be Hae Won’s answer?