In the Psych office, Shawn rigs up a camera and records himself recounting a story. He starts at the beginning when Gus got his new job a week ago...
We flashback to Gus showing Shawn his new office. The place is amazing. There's a fully stocked kitchen, and Gus gets a company car, three weeks vacation a year and a slew of sweet perks. Shawn is impressed and Gus is thrilled to finally have a job where his work is appreciated and rewarded. In addition to all that good stuff, Gus is happy to report that he thinks his co-worker, a beautiful woman whose middle name is literally "Love," could be the perfect woman for him. Gus hasn't made his move yet, but is hopeful he will soon.
The flashback ends for a beat, and we cut back to the Psych office where Shawn is speaking into the camera he had set up. He explains that after seeing how happy Gus was with his new life, he knew that it was his time to focus on his own happiness; he knew that it was time to close "Psych" and to leave Santa Barbara to be with Juliet.
We then flashback to Shawn telling this news to Juliet over the phone. She is elated that they will finally be together in the same city, but wonders how Gus has taken the news. Shawn says he hasn't told him yet.
Shawn and Gus arrive at the SBPD. Shawn is doing everything he can to avoid breaking the news to Gus that he's moving away and closing "Psych" for good. But he knows he has to do it soon, so he musters up enough courage to tell Gus that he has bad news to report. But before Shawn can explain to Gus what the news is, Lassiter interrupts and says they need help on a murder case. On their way to the crime scene, Head Detective Betsy Brannigan explains to Lassiter that she hasn't hired a new Junior Detective yet because she prefers to work alone. Gus advises her to not work alone because working alone is the saddest of situations to be in. Shawn overhears Gus saying this and begins to feel even more guilty for his decision to leave Gus behind.
They arrive at the crime scene and find the body of a man named Warren Dern lying dead on his living room floor. Gus is trying to get Shawn to tell him what the bad news is, but Shawn, again, avoids telling him. Betsy explains that Warren had no next of kin and that his in-case-of-emergency contact is his best friend and business partner, Ian Collins, who is there at the crime scene with them answering questions. Ian explains he and Warren were in real estate together until Warren left the partnership to start his own venture; which is odd because the business they ran together was doing well. While Shawn is listening to all this, he can't help but notice that Ian and Warren's situation parallels his situation with Gus. He becomes visibly and vocally uncomfortable. In that moment, Lassiter realizes why Shawn is acting like this, so he takes Shawn aside to have a talk. He tells Shawn he knows he's leaving Santa Barbara to be with Juliet and that he hasn't told Gus yet. Lassiter advises him to take Gus to a happy place filled with old memories, so that when he breaks the news to Gus, the blow will be a bit softened. Shawn thinks this is a great idea, so he hugs Lassiter and tells him this is the best advice he's ever given him.
At the morgue, Brannigan and Woody discuss the scratches on the body, the dirt all over him and the raccoon scat found under his fingernails. Brannigan thinks he was rushing to uncover something buried in the ground. Woody adds that there were also traces of moss and a rare breed of mushroom called "playa." Armed with these clues, Betsy thinks she knows where Warren was digging before he was killed. She figured it out before Shawn did, which worries Gus. Their jobs at the SBPD are starting to become obsolete because Brannigan is always two steps ahead of them.
They arrive at the hole Warren dug up in the woods. Betsy finds it odd that the hole is so small. Shawn immediately starts looking for clues, but every clue Shawn sees, Brannigan sees it first. She spots two different sets of footprints near the hole; a size 10 ½ shoe, belonging to Warren, and the other, a size 12 shoe, possibly belonging to an unknown accomplice. She finds a toll booth with a camera nearby and thinks it could be her ticket to identifying the killer.
She brings these clues back to the SBPD to do some further investigating. She watches the toll booth footage and confirms that Warren had indeed driven to the hole with another person, perhaps an unknown co-conspirator. She is able to identify his name, Klaus Goedecki, and quickly finds a location on him. They head to the hotel where Klaus is staying, enter his room and find him lying dead on the floor.
Back at Gus' office, Shawn tells Gus' co-worker Love that Gus is going to need someone to take care of him. But Love doesn't even know who Gus is, and now Shawn is even more worried knowing the girl of Gus' dreams may never be his. The bright future Shawn saw happening for Gus is slowly starting to dim.Shawn heads to Henry's house for some advice. While Henry is busy prepping to fill in for a professor who teaches a criminology class, Shawn says he needs to tell someone something serious, but he doesn't know how. Henry gives him a bit of general advice. He tells Shawn to be straightforward, but to break the news to this person while he or she is in a good frame of mind; that way the bad news won't feel as devastating. This advice, coupled with Lassiter's advice, helps Shawn determine what he needs to do. He needs to solve the case with Gus before Brannigan solves it. When they do solve it, they'll be elated, and the news of Shawn leaving Gus won't feel as bad.
Shawn brings Gus back to Klaus's hotel room to find more clues. Gus thinks it's a lost cause because Brannigan is probably very close to solving the case already. However, Shawn ends up finding new clues that lead them closer to the truth. It turns out Klaus was actually a hitman. His hotel room wasn't robbed or broken into; Klaus let the killer into his room because he knew him. Shawn then finds a hidden map leading to a buried treasure in the woods. Gus says they already found the hole in the woods earlier, but after he takes a closer look at the map, he realizes that the hole they found earlier was in a different location. They were digging in the wrong place. Whoever killed Klaus was looking for this map, but couldn't find it.
Shawn and Gus follow the map to the correct location of the buried treasure in the woods. Gus starts digging and is mortified to find a body buried there. They bring it back to the morgue and Woody tells Shawn the body belongs to a man named Chris Cheramie. He was killed with a 9mm gun, and there are bullets riddled all over his body. From this, they know Klaus wasn't the one who killed him because a professional hitman would have been more accurate. Gus does an Internet search for "Chris Cheramie" and finds out that Chris came to town to bid on a property of land, but he never made it to the auction. The people that actually won the auction were Warren Dern and his partner Ian Collins. From this, they determine that the real killer is Ian Collins. Woody points out that he found brake dust on Klaus's clothes. Shawn then asks Woody if his car was impounded, and it turns out it was.
Shawn and Gus go to check out the car in the impound lot. Underneath the car, they find a 9 mm gun in a plastic bag. Gus suggests they get this evidence over to Lassie immediately, but Shawn tells him they need to make a stop first. Shawn takes Gus to their old high school, Leland Bosseigh High. Gus is confused as to why they are there and tells Shawn that he's been acting crazy this entire investigation. Shawn finally admits to Gus that this is their last case together, and that he wanted to take Gus to their old high school because it's filled with great memories. Gus is confused. Before Shawn can explain, Ian Collins shows up pointing a gun at the both of them.It turns out Ian had been following them the whole day. Ian knows they have the murder weapon, and he threatens them at gunpoint, telling them to hand it over. Shawn tells Ian he knows what really happened and starts to break down the case. Three years ago, Ian and Warren killed Chris Cheramie, their rival in a land deal. Ian buried the body in the woods. Unknown to Ian, Warren buried the murder weapon so he could use it as leverage if he ever needed it. So years later, when Warren abruptly left his and Ian's business, Ian hired a hitman to kill Warren. Ian knew if he killed Warren himself, he wouldn't have an alibi and he'd get caught. When the hitman went to kill Warren, Warren told him that he had the murder weapon with Ian's fingerprints on it. After retrieving the murder weapon from Warren, the hitman killed Warren with his own gun and fled the scene.
Ian knows he's been caught. He chases Shawn and Gus through campus, gun in hand. Shawn and Gus make a quick getaway in the Driver's Ed car, which has two steering wheels, two gas pedals and two brake pedals. Ian drives after them, trying to catch up. In a panic, Shawn calls Henry for back up. Henry is in the middle of teaching a criminology class, so he tells the few students who actually showed up that they're going on a field trip.
Henry and his students arrive at the road Shawn and Gus are being chased down. Henry spots Ian's car and shoots Ian's tires out, bringing him to a halt. The cops show up and Henry guides Ian over to be arrested. The students are impressed with Henry, thinking this is the best class they've ever taken.
The case is now solved, and Shawn knows the time has come to finally break the news to Gus, but he can't. He can't bring himself to do it in person... We then learn that the video of Shawn recounting this whole story is actually a "goodbye DVD" he made for Gus explaining why he couldn't tell him this news in person.
When Gus watches the DVD, he's shocked. He listens to Shawn's whole story about why he's leaving Santa Barbara and why it was so hard to tell him. In the video, Shawn says to Gus that he knows he'll be OK without him, and that he believes he was the one holding Gus back; that he had kept him from the life that he really wanted, the life he truly deserved. If he hadn't barged into Gus' office 8 years ago and said, "We're going to play detective whether you like to or not," maybe Gus would have had a different life; perhaps a better life. Gus turns the video off and tries to process it all.
Moments later, Gus heads over to the Psych office to see if Shawn is still there. Gus is surprised to find Henry there as well. Henry is there scoping out the office with a measuring tape, appearing as though he may use the space for himself someday. Henry tells Gus that Shawn made him a goodbye DVD too. It turns out Shawn sent goodbye DVDs to everyone; to Woody, to Lassiter and even to the mysterious Officer Dobson (whose face we finally see after years of solely mentioning his name).
In the goodbye DVD to Lassiter, Shawn recorded himself admitting the truth that he is not a real psychic. Lassiter watches it, but shuts it off right before the part where Shawn's about to admit it. Lassiter knows what Shawn was about to say, and he didn't feel the need to hear it. Shawn did more good for the SBPD than Lassiter could have ever imagined, and for that he will be forever thankful. Even though he'd never admit that out loud. Just then, Betsy stops by Lassiter's office to tell him she wants Buzz McNab to be her Junior Detective. Even though Buzz had the lowest score on the detective's exam, Betsy isn't phased. She knows that under her tutelage, she can mold Buzz into a brilliant detective. Lassiter is shocked to hear this, but trusts Betsy's instincts and approves it anyway. Buzz steps in wearing a suit and tie, excited for his new position on the force to begin.
Shawn arrives in San Francisco and immediately goes to see Juliet, who's in the middle of investigating a crime scene. Chief Vick is there too. Suddenly, to everyone's surprise, Gus shows up. He's pissed that Shawn left without saying goodbye. He then launches into the story detailing the reason why he drove all the way to San Fransisco to tell him that in person... Gus was about to give a presentation at work, but found Shawn's goodbye DVD on his desk and decided to watch it first. Shawn's words made Gus realize that his "real job" as a pharmaceutical salesman was never his real passion, and that he doesn't want to live his life behind a desk anymore. Solving crimes with Shawn has been the best part of his life for the last eight years, and he doesn't want to give that up. So he decided to do something really bold, the boldest thing he's ever done, and move to San Francisco to keep "Psych" and their friendship alive.
Shawn is shocked and overjoyed to hear this news. They're going to set up "Psych" in San Francisco and solve crimes for Chief Vick and the SFPD full time, and it's going to be awesome. Juliet and the Chief say they already have a consultant, a who man with obsessive compulsive personality disorder (a nod to Adrian Monk from USA's hit show "Monk") . But Shawn isn't worried. He knows he and Gus will do a better job.
Shawn's next move is to tell Juliet that he's never going to shy away from the big decisions ever again. He launches into a lengthy speech, telling Juliet that when he's with her he feels fearless and unbreakable, and that he never wants to be without her. He pulls out an engagement ring and proposes to Juliet. Juliet says yes, but before Shawn can put the ring on her finger, a mugger steals it from Shawn's hands and gets away. Shawn, Gus and Juliet immediately hop in the Driver's Ed car. They chase after the robber, and it feels just like old times.
An exciting new chapter in each of their lives has officially begun.