Newlyweds Nana (Tomoyo Harada) and Shota (Kei Tanaka) move into a residential flat, excited for their new life. But at a residents' meeting, Nana joins a "murder-swap game," where people write down someone they want dead and draw names. What starts as a harmless game soon becomes a terrifying reality. ©NIPPON TV

Building manager Tokoshima (Naoto Takenaka) falls to his death from the roof. On the apartment bulletin board is a note reading "Manager." Is this the start of the terrifying murder-swap game? Shota worries about Nana, who is in shock, while Nana tries to hide the game from him. But the tragedy is far from over. ©NIPPON TV

TV talent, Doctor Yamagiwa is murdered, and threats against Fujii intensify. Fujii suspects someone in the building killed Yamagiwa to blackmail him, but rumors spread that Fujii is the killer. As Shota shares his theory with Nana, Fujii searches for "Masao Tanaka," the name on the paper he drew. ©NIPPON TV

Three people whose names were written in the game have died one after another. At a residents' meeting, someone suggests revealing whose names they wrote, but no one agrees. Meanwhile, Shota hears about the murder-swap game from Ono and is shocked to learn Nana has been lying to him. Among the residents is the next victim. ©NIPPON TV

Nana says they should tell the police about the murder-swap game, but the residents object. Later, someone confesses to writing Misato Akaike's name. Nana is shocked to learn Shota already knew about the game, while Shota sees her secretly meeting Asao. Is their relationship beggining to break? A new victim then appears. ©NIPPON TV

Kuzumi feels responsible after actor Yoshihiko Hakamada is killed. Nana tells Shota that she wrote "Asao Hosokawa" and reveals her true relationship with him. Meanwhile, Kayo Kojima in Room 102 is obsessed with the children in the building. As Nana and Shota seek the truth, another victim appears. ©NIPPON TV

Kayo Kojima is murdered, and only her foot is found. Nana and Shota think Sumika, who wrote Kayo's name, should tell the police about the game. Then officer Masashi, Sanae's husband, arrives with Detective Kamiya, who takes over the case. Troubled by threats, Kuzumi turns to Ukita, who suspects the killer and takes action. ©NIPPON TV

Nana is questioned by Detectives Kamiya and Mizuki on suspicion of posting an online request to kill Asao. Determined to uncover the truth, Shota gets Tamiya to reveal the names he wrote and drew. He gathers Sanae and Kuroshima, then names four residents who may have killed Ukita, including an unexpected person. ©NIPPON TV

Kono, whom Nana was supposed to kill, is murdered. Who killed him in her place? Nana suggests moving to Shota, still troubled by the "Room 302 resident" note Kinoshita showed her. After talking with Detective Kamiya, they suspect Sanae has killed someone. As Shota investigates her, a shocking secret emerges. ©NIPPON TV

Shota and Kuroshima are imprisoned by Sanae in a hidden room in Room 402, where they learn the identity of a mysterious boy. Nana hears Shota is absent from work without notice and visits Room 402, which he broke into the night before. Sanae calmly offers to help search. As Nana investigates, she discovers who killed Dr. Yamagiwa. ©NIPPON TV

A man's counterattack begins after his beloved wife is killed. Shota reports the video showing Nana's final moments to the police. Kamiya brings in the cyber team, but they cannot identify the poster. Frustrated by the stalled investigation, Shota attends a residents' meeting, where new Room 304 resident Nikaido appears with his crime-solving AI research. ©NIPPON TV

Shota and the others enter Kinoshita's room, but who is she and what is her purpose? Shota forcibly takes the residents' trash she collected and searches it. When he finds a condolence envelope in Kuroshima's trash, he grows suspicious of her. Later, after visiting Nikaido with hot pot, Shota returns home to find Ono in Nana's study. ©NIPPON TV

Realizing the police may catch them after Iqbal's group attacks Shota, Xinyi helps her undocumented boyfriend Cuong escape. Shota and Nikaido attend an emergency residents' meeting, where new resident Minami appears. The residents grow wary as he bluntly asks about the case. Suspected of murder, Fujii tries to confess everything… ©NIPPON TV

Shota visits Kuzumi after he wakes, but Kuzumi has completely changed. During questioning, Sanae confesses, though she seems to be protecting someone. Nikaido's AI suggests the same pleasure killer murdered the Akaikes, Ukita, and Nana, and the suspect is unexpected. On summer festival night, a new victim may appear. Who will be targeted? ©NIPPON TV

Shota, Nikaido, and Minami learn from Mizuki that Kuroshima was pushed onto the tracks. Kamiya is suspended for bribery and covering up the murder-exchange game, but continues investigating alone and uncovers a surprising truth. Shota realizes the mysterious voice he heard while captive was Kamiya's. As residents confront Minami, he reveals his true identity. ©NIPPON TV

Kamiya is brutally murdered, and Shota and Mizuki vow to solve the case. Following Shota's advice, Nikaido asks the discharged Kuroshima on a date to a sunflower field, unaware her stalker Uchiyama is watching. As new facts emerge, one person suddenly becomes a prime suspect in the serial murders. Who could it be?　©NIPPON TV

After a device fires a dart into Uchiyama's chest, he soon dies. A video then plays from his computer, leaving Shota, Nikaido, and Mizuki speechless. Shota and Nikaido confront Minami about why he was at Uchiyama's apartment, but he says he was "just looking for material." What is his true purpose? Then, a dangerous resident finally runs wild. ©NIPPON TV

Minami attacks Tamiya, believing he killed a girl in Kochi five years ago. What is the real reason he moved in, as told to Shota? Kuroshima worries when she cannot reach Nikaido, but he is in Ono's room. As secrets in the confession video, Sano and Kuzumi's connection, and Sano's true identity emerge, what killer profile will the AI reveal? ©NIPPON TV

Nikaido's AI names Kuroshima as a prime suspect. Shota doubts her, while Nikaido defends her, causing tension. Tamiya, who turned himself in, reveals a murder. As new evidence raises suspicions around Ono, Fujii, and Sakuragi, and Kuzumi's fate remains unclear, Shota uses a clue behind the puzzle to lure out the mastermind. Who will appear? ©NIPPON TV

Shota wakes after being choked out by Nikaido to find his hands and feet bound, with an IV in his arm. Kuroshima is tied up beside him. Then Nikaido appears before them. Meanwhile, Kinoshita confronts Nishimura about Tokoshima's murder. At last, the full truth behind the murder-exchange game is revealed. Who is the serial killer? ©NIPPON TV

After Nana's funeral, a dazed Shota finds the diary she left behind, filled with memories of their life together. Then an email arrives on the computer. Meanwhile, Detectives Kamiya and Mizuki begin examining whether Shota could be the mastermind behind the serial murders. A moving special episode traces Nana and Shota's story from their first meeting to his proposal. ©NIPPON TV