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.

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.

When the daughter of a Chinese Triad family disappears, Shawn and Gus take on the case.

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.

When a woman is found dead with a bottle of pills that are lab trial samples, Lassiter and Gus, who are taking the same tap class, team up to dance their way to catching a murderer

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

Shawn has to face serious competition when a talented criminal profiler named Declan Rand comes to Santa Barbara to help solve the murders of donors on a liver-transplant list.

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

Shawn and Gus help a prison guard locate his escaped inmates while on a ferry boat headed to the Channel Islands.

Due to an unlawful entry into a criminals property, Shawn gets suspended from his consultant postition and gets Henry fired from his position at the SBPD at the same time. Shawn has a series of Scrooge type dreams where Tony Cox is his 'spirit guide'.

When a polar bear trainer is found dead, Shawn works to prove the bear's innocence.

When a member of a gang of car thieves turns up dead, Shawn and Gus must infiltrate a drag racing ring to find the killer. Shawn soon finds himself enjoying the fast lane too much, which not only endangers the investigation but also their lives.

When they solve a case without following proper protocols, Shawn and Gus are ordered by the Chief to take a crash course at the police academy in order to learn the correct way to handle cases, but the two resort back to their old ways.

When a spy is framed for a crime she didn't commit, she decides to use Shawn and Gus to prove her innocence.

While on the haunted house ride at Santa Barbara's Scare Fest, Shawn and Gus witness a murder and are soon led to believe the person who committed it is the ghost of a man who fell to his death at Scare Fest 13 years ago.

A wealthy widow's young date is murdered, pitting Shawn and Gus against a dirty rotten scoundrel they are convinced trained the victim to be a con artist.