Episode 10 of Strong Girl Nam-soon begins with Geum-ju being rushed to the hospital as Gang-su, Shi-oh’s henchman, looks on from the sidelines. Shi-oh calls Gang-su from his office to confirm which hospital Geum-ju was taken to and orders him to finish the job.
Nam-soon looks on, unable to do anything. Gang-su begins to drive his truck but it suddenly stops. He gets down and finds the wheels are all punctured by darts. Hee-sik arrives at the hospital just as Joong-gan is getting her husband admitted.
Nam-soon pretends to still be on Shi-oh’s side. She asks him if he has hired her to kill people. He asks her if she can do it and she says she can.
At the hospital, Joong-gan leaves Geum-ju a voicemail detailing what happened with her father, Guk-jong. The doctor tells her that he’ll need surgery. He also informs her that Geum-ju has been hospitalized.
Joong-gan rushes to Geum-ju’s room and enters despite two security guards trying to stop her. She finds her daughter with bandages all over her face and breaks down. In the midst of crying she gets a phone call from Geum-ju herself. Geum-ju is, in fact, perfectly fine and is seated in the security room watching the camera feed. She tells Joong-gan that the woman in the hospital bed is her stand-in.
A flashback shows Geum-ju telling Nam-soon that she meant to provoke Shi-oh so that he’ll make a mistake. But she’s made arrangements to protect herself.
At present, Nam-soon gets a message from her mother and is relieved to know she’s okay. Nevertheless, she insists she will get revenge on Shi-oh. When Ms. Baek enters the restroom she’s in, Nam-soon asks her where the item labelled CTA4885 would be. She directs Nam-soon to Manager Heo, her ex-boss.
Nam-soon heads to the warehouse where he is cleaning up the mess left by Shi-oh. Nam-soon sees a box labelled CTA4885 but the manager doesn’t tell her what’s inside.
At the police station, the detectives have figured out how the drug affects the body. They also realised that the recently deceased Doogo employee was having the drug, ingesting it through an energy drink. This means the drug could be out there in various different forms. Furthermore, a camera has caught Gang-su’s truck, showing how it automatically changed its licence plate.
Joong-gan meets Geum-ju in secret. The latter tells Joong-gan that someone is trying to kill her. A flashback shows that Geum-ju noticed when the truck started to follow her. She gave Hee-sik the licence plate and then orchestrated her own accident with the help of her Opulentia contact.
Back in the present, Geum-ju finishes her explanation and tells her mother off for beating her father. Na-young sends out a notice about Geum-ju’s absence. The email is received by Madam Kim of the Heritage Club as well. Thanks to the bug he planted in the previous episode, Hee-sik overhears Kim speaking to an employee about selling an antidote.
Meanwhile, Bong-go is taking care of Nam-in, who is still unwell. At the house, Geum-dong is upset about everything with his father. He asks Na-young to take him to the hospital but she refuses.
At Bread Song’s office, Hong-do gets the email about Geum-ju. He conveys the news to Song, who is taping up the photograph of him and Shi-oh. This photograph really seems to touch a nerve.
Nam-soon wonders how to get information out of Manager Heo. When everyone leaves, she gets a call from Shi-oh. She enters his office and sees him drinking a blue liquid. He asks her to have dinner with him.
Geum-ju gets a text from Bread Song and replies pretending to be her secretary. She tells Song that she’s in room 707 of the hospital. Geum-ju’s father, Guk-jong, is wheeled in and Geum-dong soon follows, crying.
Shi-oh and Nam-soon go to a Mongolian place for dinner. She asks about Shi-oh’s past and he admits he’s an orphan and was raised in Russia. He asks about the secret of her strength and she tells him it runs in the family.
Hee-sik watches it all through the camera in Nam-soon’s watch. By listening to the other recorded conversations, Hee-sik has also realised that Paul is the codeword used for the drugs. Hee-sik is then told that Dong-seok never reported to the Busan team.
We see that the team leader is standing in a trance by the seashore. He wades into the water and it takes 3-4 men to pull him back. They’re about to call the cops when he just gets up and walks away.
Nam-soon then hears a phone call that Shi-oh takes in Russian. Hee-sik translates it to reveal that the item CTA4885 will be shipped soon. Nam-soon panics when Shi-oh offers to drive her home but Hee-sik tells her to go to his place.
A flashback shows the young boy at Pavel being forced to shoot a man who betrayed the gang. Binbin is there too. Nam-soon enters Hee-sik’s apartment and drinks a full bottle of water since she was tipsy from the drinks.
Back in the hospital, Guk-jong claims to have left home in search of Nam-soon. He searched for her in the mountains because she liked high places. So he reached Tibet and ended up joining the monks. He’s overjoyed to hear that Nam-soon returned and is ready to be a faithful husband. Elsewhere, Jun-hee tells Joong-gan he won’t give up on her.
Hee-sik comes home to find Nam-soon passed out on his sofa. When he leans down to wipe something from her lip, she suddenly opens her eyes and kisses him. Hee-sik jumps away and they awkwardly cover it up. She then tells him that Shi-oh is definitely taking the drug. They decide they must intercept the CTA4885 shipment.
Later, when Hee-sik is having ramen, Nam-soon asks for a bite and gets another kiss instead. Bong-go tries to find out where Nam-in got the diet pill from but there are no clues.
Myung-hee is given a job and a place to stay thanks to Geum-ju. She tells Na-young about Shi-oh’s visit and his questions about Nam-soon.
Bread Song and Hong-do visit ‘Geum-ju’ in the hospital. Na-young informs Geum-ju about it but she’s convinced Song isn’t clever enough to learn the truth. But turns out, Song realises that the woman is a fake. Apparently, he was able to tell from the shape of her nostrils.
Nam-soon meets Geum-ju before leaving for work. Since Shi-oh has suspicions, Geum-ju tells Nam-soon to stay at Hee-sik’s place for the meantime. This way, Geum-ju hints, she can become closer to Hee-sik as well.
Bong-go comes to the police station and shows Hee-sik the pill Nam-in was taking. He asks him to analyse it.
Nam-soon tells Ms. Baek she will be out of the office for a bit and asks her to cover for her. Nam-soon goes to the warehouse and sees the boxes being put inside a truck. She jumps in and hides. She then opens one of the boxes and finds a jacket inside.
Hee-sik and Young-tak stop the truck on its route, with Hee-sik dressed as a woman, pretending to have car trouble. He distracts the driver while Young-tak opens the back and takes the jacket from Nam-soon as she jumps out as well. It all works out.
Hee-sik cuts into the jacket at the police station and finds it is filled with feathers. He puts one of them in a bit of water and the feather dissolves into the drug.
Nam-soon runs back to the office as Ms. Baek informs her that Shi-oh has been looking for her.
Hee-sik is told that Nam-in’s diet pill is also a synthetic drug. He conveys the news to Geum-ju, who is shocked. Nam-soon enters Shi-oh’s office, and he pulls her close, asking her if she will go out with him.