A night of partying which no one remembers that turned deadly sets Shawn, Gus, Woody and Lassiter on the trail of their deeds and a way to clear their names of suspected murder. Unfortunately, they may have to depend on Shawn's "psychic" memories of the night's events.

After eluding capture and disappearing eight years ago, the famed Yin Yang serial killer is back, and he's set his sights on Shawn.

A serial killer targets Shawn using scenarios from classic Hitchcock films.

Shawn and Gus help Detective Lassiter enlist the help of Henry and Woody to solve the murder of a real estate executive. Meanwhile, Shawn struggles with a life decision.

The episode kicks off with Shawn and Gus receiving a mysterious e-mail inviting them to the annual Cinnamon Festival in Dual Spires, a quirky Northern California town nearly invisible on the map. When they arrive the pair quickly find themselves embroiled in the mysterious death of local high school student Paula Merral. As Shawn and Gus unravel the many secrets of the town, they meet several local residents including town doctor/lawyer/veterinarian Donna Gooden, Sheriff Andrew Jackson, proprietors of the local diner Robert and Michelle Barker, the mysterious Woman with Wood and enigmatic bookish beauty Maudette Hornsby. The pool of suspects proves to be deeper than suspected as Shawn and Gus must work to figure out who killed Paula Merral.

After Gus accidentally tampers with the crime where his boss was killed, Shawn helps him find the real murderer before Gus is arrested.

The star of a Spanish telenovela has been murdered by another actor on the show. The murderer insists that it was an accident and claims that the prop knife was switched with a real knife without his knowledge. Shawn and Gus believe that he was framed and investigate the crime. Gus is especially excited to be working on the set of his favorite soap opera, but it's Shawn who gets a recurring role on the show.

Shawn and Gus are hired by a childhood friend to find a missing camp counselor who disappeared near their old sleep-away campgrounds. Upon their arrival, spooky activity abounds and they must uncover if the dark past of the abandoned camp has come back to life.

While investigating a possible crime, Shawn stumbles upon one of a pair of criminals, gets shot, and is dumped in the trunk of a car.

Lassiter hires Shawn and Gus to get to the bottom of strange occurrences at his new condo.

Shawn and Gus attend their high school reunion. Shawn sees a body fly past a window, but on further inspection the body has vanished. When Gus assumes the worst, and Lassiter refuses to help, Shawn seeks assistance from Juliet.

Shawn and Gus return to Vancouver to visit their old nemesis Despereaux in prison at the felon's request, who then uses them to escape and pull one last job before he is extradited to the United States. Only while he is out, he is framed for the murder of a Crown Attorney and now asks the guys for help clearing his name of this most recent – and frankly unseemly – charge.

Shawn and Gus go undercover as talent show contestants to investigate a number of failed attempts to kill one of the judges.

Shawn and Gus get themselves hired onto the case when an unstable lawyer claims his assistant was abducted by aliens.

A body relating to a 20-year-old case is finally found, and Shawn, Gus, and Henry revisit all the old suspects in order to solve the case

On the 100th episode of Psych... Shawn and Gus attend a party hosted by an aging rockstar named Billy Lipps, a man the SBPD arrested years ago for a murder he doesn't remember committing.

The gang spends the weekend at a casino resort for a wedding and crosses paths with a local crime boss whose presence jeopardizes the impending nuptials.

Juliet asks Shawn and Gus for assistance on her undercover assignment. They're only too glad to help, since it involves sorority sisters. Unfortunately, what's supposed to be an easy case turns out to have ties to their past and may endanger Juliet. Meanwhile, Lassiter locks horns with the oldest rookie the departments has ever trained.

Lassiter and Juliet get called to a museum to investigate the disappearance of a 3,000-year-old mummy. Lassiter insists it's just a prank that's not worth his time. He's busy working on another case involving the death of philanthropist William Wyles III. However, the assistant curator insists that something weird is going on, something possibly supernatural that requires special help. Shawn is then brought in on the case, and he declares that the mummy was not stolen, iit walked away on its own.

Gus is taken hostage at the Santa Barbara Savings and Loan Bank while making a deposit for Shawn. Shawn, still in the car and oblivious to the hostage situation, questions Lassiter and Juliet about the cops' sudden arrival. Learning that his best friend is in trouble, Shawn is desperate to help and realizes he needs to get inside the bank to question the gunman. However, the SWAT team soon shows up, and its negotiator will not easily satisfy Shawn's request.

Shawn and Gus must prove Lassiter's innocence when he's on the hook for a murder inside of the Santa Barbara Police Department.

Shawn and Gus spot an art thief whom Lassiter has been trying to arrest for years. So, although they are on a skiing vacation in Canada, they appeal to the local constabulary with mixed results: someone gets axed, another finds himself interrogated and Pierre Despereaux may get away scot-free, once again.

Shawn and Gus work with two retired police officers to solve the murder of a police chief.

The Yin/Yang trilogy comes to a thrilling close as Shawn and Gus race to save a woman kidnapped by Yin. Only this time, they are forced to use Yang's knowledge of Yin to solve the case by allowing her to accompany them on the investigation.

Shawn and Gus team up with Despereaux to locate a mythical dagger rumored to be the key to unlocking a dead billionaire's treasure.