Michael is jogging and disgusted when he has to dodge a woman walking her dog, two men arguing, and a crazy man trying to sell his belongings. As Michael gets home and realizes that he's stepped in dog shit, he calls Hannah, who is in Oregon checking out a university to attend. She's clearly impressed by the state and doesn't want to hear anything negative from her husband.
Michael is disgusted when he gets stuck in LA traffic while driving Rex to school. When he gets to the office, Bird reminds him that they have several open cases. However, Michael decides to go jogging in the hills of Griffith Park. As he admires the view, he hears a dog barking and goes to investigate. The detective finds a corpse propped up against a tree, his wrists vertically slashed and a Roman numeral "II" carved into his chest.
Michael calls in the murder and heads back to the station, and they confirm that the infamous Gemini Killer committed similar murders across the U.S. starting in 1999. He was killed by the FBI a year ago and Captain Harper wonders if a copycat killer is responsible. Bird points out that Gemini always left a second victim at a similar location, and Harper agrees to let them put men out to cover other parks in the area. She then has Michael pick up the FBI profiler that she's requested.
Michael picks up the FBI profiler, Elizabeth Santoro. She's talking to her ex-husband on her cellphone and they're discussing her daughter, who doesn't want to talk to her. Once Santoro hangs up, Michael drives her to her hotel. En route, she explains that she worked the Gemini case for 12 years. Once he was killed, she took a leave of absence to write up a book on the case. One of the facts that the police never revealed to the public was that Gemini always left a $2 bill on his victims' bodies. After Michael drops Santoro off at her hotel, he drives to Griffith Park and meets with Bird. Suspecting the dog may have eaten any evidence, they search the area and finally locate it. Once they sedate it, they take it to the morgue and Dr. Banks checks its stomach and confirms that it swallowed a $2 bill inside.
When the detectives tell Harper and Santoro what they've found, Santoro insists that Gemini is dead and that their new killer must be a law enforcement officer with access to the confidential case files. She wants them to check on the files of disgruntled ex-law officers, and shuts down Bird when he points out that they never positively confirmed the man she shot was Gemini. After the meeting, Michael approaches Santoro privately and suggests that she might have made a mistake. He tells her how he recently cleared an innocent man who he had put in prison for ten years, but Santoro insists she didn't make a mistake and that she's there to prevent a second victim from dying.
The killer is at an abandoned building and prepares a set of medical tools, a packet of $2 bills, and a hypodermic needle.
Michael calls Hannah to ask where his phone charger is while going through the drawers. He gets her voice mail and leaves a message, but then finds the charger in a drawer. Michael also finds an estimate from Mountaintop Moving & Storage for a delivery to Oregon.
Later, Michael meets with Dr. Lee and admits that he feels Hannah lied to him. He thinks that Hannah is happy in LA, but the psychiatrist suggests that Michael might just be hearing what he wants to hear. Lee has Michael imagine what Hannah is feeling and the detective realizes that she's happy to have a chance to go somewhere that she can start over and be happy. The psychiatrist suggests that Michael is worried that Hannah will leave him, and admits that in most marriage, the partners simply lose shared interests, wander away from one another, and discover that there's no way back.
At the office, Vega notices Michael looking up Oregon on the Internet. He explains that he has a lead on a home invasion break-in and a CI gave him the address of the fence who handled the stolen goods. As they drive to the pawnshop, Vega talks about how he could never give up LA. When they arrive, they discover that there's nothing at Vega's address but a closed storefront with a graffiti tag painted on the shutters. When Michael confirms that Vega paid $100 for the tip, he explains to his partner that he's been suckered.
That night, Michael pensively studies the moving estimate and tries to call Hannah. When she doesn't answer and his call goes to voice mail, Michael hangs up without leaving a message.
Michael suggests to Bird that they check cheap motels in the area, because Gemini used them as bases of operations near his murders. They tear up the list and start checking motels, and Michael strikes out at one motel. However, as he leaves, he sees Mountaintop Moving & Storage across the street. Remembering the estimate in the other reality, he goes over and discovers that the building is abandoned and closed up. Michael breaks in and spots a man moving in the shadows. When the detective tells him to stop, the man runs off and Michael chases him to the roof, but when he steps out there's no sign of the killer.
The CSI team goes over the room and finds a sleeping bag containing $2 bills. Michael notices a napkin with the graffiti tag symbol on it. Before he can examine it, Harper asks Michael why he was there. The detective explains that he was checking out the motel, saw the abandoned building, and thought it looked suspicious. Santoro, listening in, clearly isn't convinced and asks for more details. Michael has to leave with Bird, while Santoro talks to Harper and notes that his name was among those in the disgruntled officer files. As they talk, the killer listens in from an air vent where he's hiding.
Outside, Michael tells Bird that he'll meet him at the station once he picks up Rex. However, he drives to the pawnshop address in this reality. There is no graffiti tag on the wall. When he goes back to the station, Harper calls Michael into her office and plays him a tape of the killer, who called for Santoro. The man boasts about evading Santoro for twelve years and mentions her book, admitting that he didn't want her to dismiss his current work as belonging to a copycat.
Once the tape is done playing, Harper tells Michael that the call came from his home. He angrily tells her to get a squad there before Rex arrives, but Santoro interrupts to point out that she only told Michael about the book. The profiler also points out that Michael is the one who found the corpse and all of the evidence that indicates Gemini is responsible. Santoro checked the identity of the first victim in the hills and notes that he's a convicted sex offender, and figures that Michael would have killed the man as punishment. When Michael starts to yell back, Harper breaks them up and gets him to agree to search his home and car. While skeptical of Santoro's accusations, Harper does wonder why Michael searched that particular building. He doesn't have a good answer and Harper tells him to turn in his gun for the time being.
An hour later, Bird comes to see Michael and tells him that he picked up Rex to be on the safe side. He admits that he agrees with Harper that Michael is acting suspicious, and that Michael has been ever since he came back to work after the accident. Bird assures his partner that he doesn't believe he's Gemini, but he does think that something strange is going on and that Michael is shutting him out while pretending that nothing has changed. Michael can't tell him what's really going on, and Bird shows him the photos of the crime scene that he stole from the evidence room and suggests that Michael try his intuition again. They go over the photos and Michael sees the napkin from earlier and realizes that it's a logo. They check and confirm that it belongs to a coffee shop franchise. One of the photos also has a shot of Santoro... drinking coffee from the coffee shop. They confirm that a park is near the hotel where Santoro is staying and where the coffee shop is located.
After Santoro and the SID team finish searching Michael's house, she walks down the street to her car and tries to call her daughter. She gets the answering machine again and leaves a message asking her to call. A man comes up behind her and injects her with a sedative before she can fight back.
When Michael and Bird are unable to reach Santoro, Bird releases Michael and they head for the park while calling in backup.
Gemini drives into the park, using Santoro's FBI badge to get past the roadblock. When Michael and Bird arrive, the uniform on duty admits that he let someone in. Inside the park, Gemini prepares his scalpel and tells the barely-conscious Santoro that he couldn't bear to have her print a book saying that he lost. He wonders if she really thought the suspect she shot a year ago was him, or if she just wanted it all over. Gemini then starts slitting her wrists.
As Michael and Bird pull up, Bird gives his partner his gun back. They head through the woods and spot Gemini, who hears them coming. Bird and the backup officers follow him while Michael carries Santoro out. By the time the EMTs have taken Santoro to the hospital, Bird returns but Michael realizes that Gemini has escaped.
Later, Michael goes to the hospital and sits outside of Santoro's room. Her ex-husband and daughter arrive and the girl runs to embrace her mother.
Michael confronts Hannah with what he's learned about the movers, and she admits that she was too embarrassed because she felt hope for the first time since Rex died. She tells Michael that she's not as strong as him, but that she didn't want him to think that she was running away to forget their son. Hannah explains that whenever she sees Michael, she can see Rex in him and that she doesn't want to leave either one of them behind.
When Michael meets with Lee and tells him about the move, the psychiatrist is surprised that he wants to move to Oregon.
Evans warns that Michael could find choosing to move to Oregon in his dreams more painful that he anticipates.
Hannah starts looking for houses in Oregon for her and Michael.
Lee warns Michael that his dreams depend on him occupying the same places in both worlds.
Michael and Rex go jogging in Griffith Park.
Evans warns Michael that without the similarities in the two realities, one world or the other will fade as it becomes increasingly difficult for Michael to maintain both realities.
Lee agrees with Evans, saying that if Michael moves to Oregon in this reality, then he will eventually lose his grip on LA in the other reality.
Evans assures Michael that it's a good thing that he's moving, because it means he's accepting that one world isn't real. However, she advises him that he will fight back because that's what humans do, but eventually he'll lose. Michael insists that he's a man, not a test case, and that he'll make it work because he warns to make it work.
As Michael is stuck in traffic, Gemini calls him. He explains that after Michael almost caught him twice, he decided to check him out. He broke into Evans' office and read her files on Michael's case, and realizes that he believes he's in two different worlds. Gemini sympathetically tells the detective that the world needs people like the two of them, people who can see sideways. He tells Michael that he hopes he doesn't wake up and then hangs up... and boards a plane to Oregon.