The final chapter of W is finally starting. Kang Cheol, Oh Yeon-joo, and Oh Seong-moo all get transported back into W separately. They don't know that they're not alone and unaware that Yeon-joo is alive again. Yeon-joo stays waiting in front of Kang Cheol's hotel but never sees him. One day she spots Yoon So-hee and asks to speak with her. So-hee recognizes Yeon-joo as the woman that helped Kang Cheol escape the cops a year ago. Kang Cheol was found beaten in front of an ER and was arrested as soon as he recovered. Assemblyman Han Cheol-ho left him there to be found that night he beat him with a metal pipe. He's been in prison for the past year for murder, fabricating evidence, and forgery of an official document. However, his judgment day an appeal at the Seoul Appellate Court is tomorrow if she wants to see him. During this time, Assemblyman has had a successful political career and is currently in the lead as the presidential candidate.
On judgment day, Yeon-joo appears in court and Kang Cheol turns around as they lock eyes. For the past year, he didn't know where she went or if she decided to leave him. All he knew was Seo Do-yoon said he saw that she was alive again before disappearing from the penthouse. The appeal gets rejected and Do-yoon comforts Yeon-joo by telling her to stay strong because it's not over yet. While Kang Cheol was waiting to go back to prison, a key suddenly appears in the lock of the handcuffs. As he gets himself free a gun appears in his hand. Do-yoon gets a call that Kang Cheol escaped when Yeon-joo overhears she asks him to drop her off at a cafe. She tells Do-yoon that it'll be better if they don't stick together.
While Yeon-joo is waiting at the cafe she's hoping that Kang Cheol is safe and will know where to find her. Kang Cheol appears outside and picks her up. They banter back and forth as they take a moment to enjoy each other's presence again. Kang Cheol warns Yeon-joo about her dad's current condition. He's been in W for the past year as well but was imprisoned in a psychiatric ward. Someone with no family or friends that attacked a taxi driver and tried to steal a police officer's gun was easily declared crazy. With the culprit's memories constantly playing like a slideshow in his mind, he developed a split personality that allows the culprit's mind to take over randomly. Kang Cheol takes Yeon-joo to her dad's secret work office only he knew about inside of W.
Inside the office, Seong-moo was tied up per his request because he can't control when the culprit will take over his mind. He tells Kang Cheol to just let him die in W because it wasn't just his body that did the mass shooting, but he also killed a nurse that morning to escape the psychiatric ward. Kang Cheol rejects his request and said he'll pretend he didn't hear it.
Assemblyman Han kidnaps Seo Do-yoon and forces him to contact Kang Cheol. Assemblyman Han gives Kang Cheol an hour to bring the tablet to the basement they last met or else his friend dies. Kang Cheol leaves their hideout for a bit. While he was out, Seong-moo attacks Yeon-joo and tries to strangle her to death asking why she's still alive when he killed her already. Kang Cheol gets back in time to save her by grabbing Seong-moo and pinning him down. When Seong-moo snaps out of it he doesn't remember attacking her but notices the red marks on her throat. He reminds Kang Cheol what needs to be done to stop him cause he's a monster and will continue hurting people.
The police are starting to close in on their hideout. Kang Cheol and Yeon-joo sit at the kitchen table face to face. He removes their wedding rings and lets her know that regardless of what happens he will remove her from his family line so she'll always be safe. With that said, she needs to decide the ending of W once in for all. Both Kang Cheol and Seong-moo are fading characters and only one of them can stay by her side. Kang Cheol tells her that he will respect her decision and go with whatever she wants.