The Mentalist finale begins with a flash forward to six months later after Jane’s dismissal from the CBI. Jane, for the past couple of months has been living in Las Vegas, basically drinking and succumbing to his breakdown. During one of his drinking excursions at a local hotel bar, Jane befriended Lorelei a waitress and the two started chatting on the matters of right and wrong. Jane believes there is no right or wrong, but just the matter of what is and what isn’t.
While the two are talking, Oscar, a man who used to pay for Jane’s psychic consultations, interrupts the discussion wanting to talk to Jane. Oscar explains how he went to Jane to seek out his dead mother’s spirit, only to find out year’s later that his mother was actually still alive. Oscar demands his money back, but Jane politely explains that he spent all of the money. Of course, this is not the answer Oscar was hoping for, so he kindly explains that his enforcer will break Jane’s legs and the fee will now be $50,000. As a diversion, Jane “accidently” sets Oscar on fire using a cigarette and Oscar's own drink. Jane runs out of the bar and down an alley, but in the end doesn’t get very far. Cornered, he ends up getting punched and kicked by Oscar’s enforcer in the middle of the alleyway when the police arrive on the scene. Although, the police help Jane out of the precarious situation he was in, Jane still drunk from earlier ends up punching one of the officers and then gets tazered.
Meanwhile, in California, his former CBI team is investigating the murder of unknown man who was shot in the face. At the crime scene, Lisbon and the rest are informed of Jane’s arrest, but while the others are quick to want to lend a hand to Jane, Lisbon does not. Lisbon explains that they haven’t heard from Jane in months and when she offered help, right after his dismissal, he refused. Lisbon is not offering help, to someone who obviously doesn’t want help anyway. While the rest don’t agree with her “harsh treatment” as they put it, they will follow her lead and let Jane reach out first. Lisbon and Van Pelt follow a lead to a homeless woman called Bean, who describes a possible suspect, who may happen to be a gang member. Satisfied with the suspect description, Lisbon has Van Pelt check out the information, while Lisbon takes time for personal reasons.
Back in Las Vegas, someone paid Jane’s bail, he believes it is Lisbon, but he doesn’t care to find out why, as he continues his way back to his motel room, planning on drinking his sorrows away. He starts to do so, but it is interrupted by none other than Lorelei. Over a cup of chicken noodle soup she brought him, she explains that she is the one who bailed him out, because she thought he was a “good man who just happened to have lost his way.” The two spend the afternoon eating and watching TV, which quickly turns into something more and the pair spend the night together.
The following morning, Lorelei reveals to Jane that she works for Red John and that he is offering Jane a new life, if he chooses to accept his friendship. Jane declines the offer and all but pushes Lorelei out the door, but before she leaves she explains that he should reconsider his offer and to seek her out when he does. Jane states that he won’t, but when he closes the door after she leaves an eerie grin starts to form on Jane’s face.
At the CBI, Van Pelt finds evidence that the suspect the team is looking for is Kevin Sentron, a ‘Lobos’ gang member and decides to check it out while Lisbon is taking some personal time. Lisbon makes her way to a church to pray (probably for Jane), but as she sits down on the pew, Jane pops up behind her. Jane explains that he is faking his breakdown in order to draw out Red John, which he has. He is going to go along with Red John’s “plans” to lure Red John in a false sense of security to finally capture him, but he needs Lisbon’s help. Lisbon explains that she is really hurt and angry by Jane’s actions, but she will help him anyways. Jane thanks her and gives her a phone, saying that he will contact her when the time comes.
Meanwhile, Cho and Rigsby are questioning their suspect Kevin Sentron and he explains that he and his buddy Alfredo were driving around looking to resell some guns when the see a man shoot himself in the face. They steal the shotgun the man used on himself as well as the man’s bike and drove away. The team agrees that their “suspect” is telling the truth and the victim committed suicide.
Wainwright reaches out to Lisbon wanting to contact Jane to offer support and help in hopes to have Jane return back to the CBI. Lisbon disagrees with the idea saying that whatever Jane is going through, probably isn’t what it seems so they should just hold back for a while. At the same time this conversation is happening, Jane is talking to Lorelei about accepting the deal Red John is offering. Lorelei is happy to hear that, but before he can see Red John, Jane needs to give a gift first to show appreciation and respect. Jane agrees to give a gift, but Lorelei explains that gift must represent that Jane has truly changed and the only gift that would represent that is Lisbon’s dead body. Jane says that he can’t do that, but Lorelei understands that he isn’t at that point yet and leaves Jane to contemplate this new information.
The scene quickly changes showing Jane at the CBI offices giving a quick hello to his fellow colleagues, before stepping in to Lisbon’s office. He gives Lisbon a hug, then tells her “Good luck, love you” before he grabs his gun and fires. A series of gunshots are heard and Wainwright runs to see what has happened only to see Van Pelt and Cho hovering over a dead body which they claim to be Rigsby. They explain that Jane shot Rigsby in the face after he proceeded to leave the building with Lisbon’s body.
Jane and Rigsby and Lisbon are all hiding at a “safehouse.” The plan is to make it seem like Jane had a change of heart and is willing to accept Red John’s offer just long enough so they can finally capture the man. Lorelei calls Jane after hearing the news of Lisbon and Rigsby death and sets up a meeting point, but instead of bringing Lisbon’s body, he just needs to bring her head as further proof. But while Jane is trying to figure out how to deal with the latest situation, Wainwright has contacted Agent Darcy of the FBI to help find Jane. Darcy decides to inspect the body supposedly belonging to Rigsby, but after realizing that the height of the body doesn’t match Rigsby height on file, she knows something is up and calls for warrants to be placed on all of Lisbon’s team dead or alive.
Back at the safehouse, Cho and Van Pelt (who have been in on the plan from the very start) are going over logistics with the rest to put their plan into action. Jane goes to the set meeting place with supposedly Lisbon’s head, but finds a red bike with directions telling him where to go. Jane arrives at the set location, but there is nothing there, just the open desert, except a black limo pulls up with what looks to be Lorelei and one of Red John’s enforcers inside. Lorelei greets Jane and asks Jane what did he bring instead of the head. Lisbon and the rest of the team, who has been hearing this conversation through a wire Jane has been wearing, decides that they need to act now and get Jane out of there. All of them are about to start to drive, but then a series of black SUVs pull up and FBI agents pour out of the cars telling Lisbon’s team to get out of the car and put their hands up. Darcy arrives on the scene and Lisbon tells her of the plan and pleads with her to let them go so they can go and get Jane.
Meanwhile, Jane is getting roughed up by one of Red John’s men and then he shoved into the front seat of the limo, only to hear Red John’s voice coming from the back. Red John tells him that he's got a good friend within the FBI who found out that Jane was faking the deaths of Rigsby and Lisbon and subsequently all along. But he still tries to persuade Jane to change his mind and accept his offer, but Jane simply replies “go to hell.” Red John then tells Lorelei to cut off two of Jane’s fingers, before they let him go. Lorelei in the process of cutting one of Jane’s fingers off is interrupted by the FBI who is swarming the scene. Red John's man throws Jane out of the way and he stumbles towards the sand. Lisbon rushes out of the nearby police car and takes his hand, reassuring him. Lorelei and the other man try to flee the scene in the limo, but they don’t get very far as the car is engulfed by a series of gunshots from the FBI and is run off the road. Darcy who is the first person to arrive at the limo, opens up to backseat, where supposed Red John is only to find Agent Wainwright dead and duct taped to the back seat with a walkie talkie attached to his shirt, indicating once again that Red John is always two steps ahead of everyone else.
In the end, Lorelei is taken into custody where she is interrogated by Lisbon and Jane. Lorelei tells Lisbon of how she slept with Jane to rile up Lisbon and proceeds to call Jane “lover” throughout the questioning. Lisbon is visibly upset by this new detail as Jane never told her and just looks at Jane with betrayal and shock in her eyes. Jane seemingly ignoring Lisbon tells Lorelei she will talk, but Lorelei states that she will never give up the goods on Red John. Jane disagrees and tells her that she will and gives her a kiss on the top of her head before exiting the room and leaving Lisbon to watch on.