Shawn tracks down Lassiter's car with little difficulty after it's stolen. However, Shawn discovers that there's more to the situation than meets the eye and calls Gus back from vacation to help with the investigation.

Gus' supervisor, Frankjim Ogletree, demands that he quit moonlighting at Psych, lest he face termination. The vice-president of Gus' pharmaceutical company, however, decides to hire the duo as his wife believes that their home is haunted.

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 investigate the death of Leonald Callahan, aka Diddle, a computer cryptologist who was the baritone in Gus’s old college a capella group.

Shawn and Gus must recover a deadly pathogen before a thief releases it into the city.

Shawn and Gus are recruited into a think tank to help prevent the murder of a business tycoon, but once the group has disbanded, they realize that one of the members plans to use the assassination ideas to kill the client instead of save him.

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.