In the fourth episode of "Mad Concrete Dreams," the narrative shifts to a flashback, revealing a month-old meeting of the redevelopment team, including Nam Sang-ho, Sang-ja, Morgan Lee, Yo-na, and Dr. Jang. Sang-ho presents them with a list of buildings slated for redevelopment, and their mission is clear: convince the owners to sell at favorable prices.
The present timeline continues with Morgan Lee and Sang-ja relentlessly pushing building owners to sell at low prices. However, two holdouts remain: Su-jong of the Seyun building and Hanmaeun's owner. As Yo-na intensifies her efforts to persuade Kim-sun, a past connection between Sang-ja and the Hanmaeun owner surfaces. She visits him, attempting to convince him that the monetary offer is generous. She then places a heavy burden on her daughter, Yi-gyeong, by claiming that she owes her 3 billion in ransom during the kidnapping and any future earnings to cover Hwal-seong's medical expenses. In return, she asks Yi-gyeong to convince Su-jong to meet with her.
On Kim-su's part, she convinces Su-jong to sell the building and relocate to the States for a fresh start. Post-kidnapping, she fears for their safety, believing that the only way to escape the situation safely is by moving away and starting anew. Su-jong agrees, and they inform Da-rae of their decision.
Later that night, Su-jong receives a message from real estate agent Hee-joo. She reveals the secret of the redevelopment and the potential profits, advising him not to sell. The next day, she takes him on a tour of the redevelopment zone, including his building. He is shocked by the news that the redevelopment could yield him tens of billions and feels betrayed upon learning that Hwal-seong had kept this information from him.
He visits Hwal-seong at the hospital where Yi-gyeong suddenly confronts him about his wife seeing another woman. She then requests him to meet with her mother regarding the redevelopment.
Knowing the truth, Su-jong refuses to relinquish the Seyun building after making such strides. He raises the sale amount from 3 billion to 30 billion for Yo-na, asserting that he knows they were responsible for Kim Gyun's death and that they should compensate him for it. Yo-na sends him the video she has been viewing on her laptop, warning him to keep a close eye on his wife.
It becomes apparent that Yo-na had been blackmailing Kim Sun because the man and woman in the secret video are actually her and Hwal-seong. Yo-na had given Su-jong a final warning to handle everything quietly before sending him the video and walking out.
Upon discovering that Su-jong did not sign the deal, Kim-sun is so enraged that she yells at him on the phone. She attempts to call Yo-na for more time, but she does not answer. Her desperation intensifies when she learns that Yo-na had sent Su-jong the video and tried to prevent him from watching it.
At Real Capital, Yo-na and Dr. Jang update Morgan Lee on the bad news. Frustrated with their failure to deliver, he rebukes and dismisses them. He then calls their superiors and requests a new team. Yo-na angrily attacks him and leaves him bleeding on the floor as they head out to eat Japanese food.
Meanwhile, Kim-sun arrives at Real Capital offices looking for Yo-na. They miss each other at the elevators as they head out for food, while she goes in. She finds the original file of the video and permanently deletes it from the computer. She discovers Morgan Lee collapsed and bleeding on the floor.
As she struggles with whether to call the police or the emergency team, Yona enters the office looking for her phone. She is forced to hide under a desk, trembling in fear as she witnesses Yo-na finish off Morgan Lee and call the clean-up crew to handle the body.
At the Seyun building, Su-jong keeps getting interrupted before he can watch the whole video. This time, it's Hee-joo bringing in Sang-ho, who is in charge of the development. Earlier, she had told him that he could make so much money from the redevelopment if he had the right connections, and she brought him Sang-ho, who let him in as a shareholder who could earn 20 billion from a percentage of shareholding.
Later, Kim-sun returns to the building, asks for Su-jong's phone, and deletes the video. Su-jong becomes suspicious of how obsessed she is with the video and checks the messages where the video remains. Kim-sun grabs the phone, locks herself in the bathroom, and when she cannot unlock it, she pours water all over it. All this was of no use because the phone was waterproof, so Su-jong ultimately ends up watching the video.
He is stunned to see the affair between his wife and best friend, but Kim-sun seems unbothered and does not even explain. Their argument is interrupted by noises coming from the restroom where they had hidden the money. When they open the door, a man rushes at them, and they fight back. After the scuffle, they turn on the lights and realize that the man is Oh Dong-gi, the owner of the coffee shop downstairs. Dong-gi had gone up to fix the bathroom himself since Su-jong failed to do so and found the bundles of money.
At the end of the episode, Dong-gi lies on the bathroom floor, probably breathing his last breath as the scissors Kim-sun had brought are stuck in his neck. As he bleeds, Kim-sun and Su-jong stand over him in shock.
