Nont, a father and architect, moves into a new apartment with his new wife Rung, his step-daughter Mint from his previous marriage, and Look-khun, his young son, with the intention of starting a warm family life. The new apartment is on the 8th floor, and the other residents throw a small rooftop party to welcome them. However, a scary incident happens when Nont is found sitting in shock with a bloody knife in his hand in the bathroom. The next morning, a mysterious box is found in front of every door, leaving the family to wonder what secrets their new home holds. As they investigate further, they realize that the boxes were sent by Lydia, the previous tenant of Room 801, who had supposedly passed away.

Nont is released from prison to prove his innocence, but he's still wearing an EM ankle bracelet. Meanwhile, a video clip of the bathroom incident is leaked, causing people to view Nont as a murderer. In the apartment building, the violence continues, and Nont and Sorn, the teacher in room 802 are injured. As a result, the residents of the 8th floor are dissatisfied and want Nont's family to move out. Mint is unhappy that her father is seen as a killer and wants to find the truth to clear his name. She and Champ try to find the source of the box that was sent to them, leading them to the sender's house where they encounter another strange incident.

Mint continues to search for the truth to help confirm Nont's innocence. She begs Champ to use his social media to reveal the past of Sorn. But even then, they still do not know who the real killer is. Champ and Mint make up their minds to solve the mystery of the next room's box. They discover that Kade, who lives in Room 803, has been imprisoning innocent animals. However, the hospital calls to inform Champ that the sender of the box, who was previously hurt, has now recovered. Champ and Mint may finally hear the truth from the sender's mouth.

Champ and Mint continue to investigate until they reach room 804 of Toh and Ja. Mint sneaks into the room and discovers a box. Meanwhile, Toh and Ja return to the room and notice that the garbage can has been rummaged. Mint and Champ hide in the bathroom together and their close proximity causes Mint to blush. Champ and Mint track down and discover some shocking news. Toh catches Champ and Mint sneaking into the room, and their story begins to unravel, but just as things are getting interesting, a phone call from “The Boss” leads to a shocking conclusion.

After the incident with Sorn, everyone thinks he's the murderer who killed Dear. J’Maew the owner of Room 805, as well as the condominium juristic person. She told a news reporter that Sorn did it all. However, the power of social media still doesn't stop suspicions from rising about Toh and Ja. In addition, Mint and Champ discover the gambling den on the penthouse floor of the apartment. Champ and Mint investigate until they find the truth.

The truth behind the happy family scene of Dr. Kit, Khunying, and Namcha, in room 806 is revealed. Dr. Kit, who is a kind-hearted doctor, turns into a playboy as his various inappropriate actions are exposed on social media. Champ and Mint decide to investigate the truth at the clinic, but they are caught up in a trap that leaves Champ injured. At the same time, Dr. Kit's story is gradually revealed through a Lydia’’s page without knowing who posted it.

After a leaked clip, Nana, the beautiful actress in room 807 who dreams of becoming a leading actress, is caught in the social media storm about using her body to exchange for roles and still not getting any work. She decides to take a shortcut to stardom. Nana was angry and thought it was Dr. Kit who leaked the clip, she plans to reveal his secret by telling Champ about the mystery box that Dr. Kit received. Meanwhile, Mint discovers Champ's secrets.

After Mint's post went viral, she felt like she had been deceived by the Champ in room 808. She went to investigate the truth about the Champ from Dr. Kit, who was imprisoned, and learned about "The Boss". Mint returned to her apartment and saw Khunying behind a door. Meanwhile, Champ decided to record one last clip about his story and the mystery box, but he also uncovered some new truths about Lydia that he had never known before.

The last room, Nont's family's room 801, Champ showed Mint a picture of Lydia. But Mint was still angry and saw Champ as the killer who tried to frame her father. Mint decided to investigate Nont's past to try to understand the truth. As she delved deeper, Mint learned about Nont's painful history and the reason why her family moved into the apartment.

Nont and Mint decide to investigate the truth together. They talk to a real estate agent, who sold the apartment, to find the whereabouts of Lydia, who moved out. They follow the trail until they find a mysterious box in Lydia’'s room, which contains everything from Lydia’'s confession to the wickedness of everyone in the apartment, including their own secrets that they are unwilling to reveal. How will the story end? The consequences of past actions, selfishness of people and those who died alive because of the judgment of the social judiciary.