In the opening of episode 9 of Mad Concrete Dreams, a flashback to nine years prior reveals Su-jong grappling with the challenges of restructuring at Yongshin Trading, where he was tasked with laying off half of the workforce. Meanwhile, Kim-sun proposed sending Da-rae abroad for studies. As Su-jong contemplated leaving the corporate world to pursue his own entrepreneurial endeavors, Hwal-sung presented an opportunity to purchase the Seyun building. The plan was for an equal investment, and Hwal-sung suggested taking out a loan since Su-jong lacked the necessary funds. Su-jong covered the down payment, and the deed was placed under his name.
To finance his share of the investment, Su-jong took out loans from the bank, and Kim-gyun extended them the down payment. However, Hwal-sung failed to honor his commitment, marking the beginning of Su-jong's descent into debt. With the deadline for finalizing the deal looming and the risk of losing the down payment, Su-jong opted to take more loans, buy the building, and quit his HR job. Unfortunately, the area was no longer eligible for redevelopment, a fact that Hwal-sung had known beforehand, resulting in a significant loss for Su-jong.
In the present, Yi-gyeong kidnaps Da-rae and ties her up in the same cold room where Hwal-sung and Su-jong had previously kept her captive. Da-rae is furious that they had treated her so cruelly and kept her in the dark about their plans. She shares that she feels excluded from the world's progress because she is deaf. Her parents had discussed their plans in front of her while she was unable to hear, and she does not want Yi-gyeong to make the same mistake. Despite Da-rae's attempts to persuade her otherwise, Yi-gyeong is too hurt and insists that her parents must suffer as much as she does.
Su-jong and Kim-sun rush to the Seyun building after receiving a text from Yi-gyeong. Su-jong urges her to maintain that she helped Hwal-sung but had no knowledge of who he had kidnapped. Unfortunately, their lies are exposed this time due to a recording provided by Dong-chul, which was taken from Hwal-sung's car during his earlier meeting with Kim-sun.
Yi-gyeong, knowing full well that Su-jong was involved in the kidnapping, desires revenge. With no other choice, they are forced to kneel before Yi-gyeong and plead for her mercy towards Da-rae. She grants their wish and allows them to see Da-rae.
Yi-gyeong then demands that they record a video confessing to all their misdeeds. When it comes to Su-jong's turn, he takes full responsibility, insisting that he alone was responsible for everything. He even falsely confesses to killing Hwal-sung, who was still alive. It becomes clear that Su-jong is offering himself as a sacrifice for all their wrongdoings. He volunteers to kill Hwal-sung, who has been working against Yi-gyeong to gain control of her mother's wealth. Since everything started with Hwal-sung, it should end with him. He plans to kill him and turn himself in. All he asks is for Yi-gyeong to release Kim-sun and Da-rae and leave them with the Seyun building. Yi-gyeong agrees to the deal and has Dong-chul follow them to ensure they actually carry out the killing while she keeps Da-rae as her hostage.
Su-jong and Kim-sun do not actually intend to kill Hwal-sung but rather pull a stunt reminiscent of Romeo and Juliet. They plan to inject Hwal-sung with a medication that slows down his heart, making it appear as if he is dead. They call Kim-sun's friend and obtain the necessary supplies.
Meanwhile, Hwal-sung's mind is haunted by Su-jong's words about Yi-gyeong's pregnancy. Later that night, he enters a baby shop and buys supplies for a newborn when he receives a call from Kim-sun. She requests to meet, but he declines. She persists, and he agrees to meet for one last time. Su-jong and Kim-sun kidnap him and take him to the building he owns. Throughout this time, Yi-gyeong has been receiving live updates from Dong-chul, yet she still believes that Su-jong and Kim-sun lack the courage to carry out the killing.
The situation takes a dramatic turn when Dong-chul witnesses the brutal suffocation of Hwal-sung. The man lies motionless on the floor, and Dong-chul promptly sends a picture to Yi-gyeong, causing her to breakdown in a state of shock and grief. It seems that Yi-gyeong never imagined they would actually go through with it, so when they do, she feels a deep sorrow. Her mood suddenly changes as she looks at Da-rae, as if she too, desires to take the most important thing from Su-jong and Kim-sun. Da-rae is filled with fear and tries to back away.
Su-jong and Kim-sun call upon Dong-chul for help. They plan to throw Hwal-sung down the building to make it seem like he accidentally fell to his death. They want to use a taser to render Dong-chul unconscious so they can have a chance to revive Hwal-sung. However, at the end of the episode, it is Su-jong who gets tasered instead, and Kim-sun arms herself with a hammer to protect against Dong-chul. The alarm on her phone goes off, indicating that four minutes have passed. She needs to revive Hwal-sung soon, or he might truly pass away.
The episode ends with tension and urgency, leaving the audience on the edge of their seats as they await the next development in this intricate drama.
