"Dual Spires" is the twelfth episode of Season Five. Shawn and Gus are invited to a festival in a small town and arrive to find themselves embroiled in the mystery of a drowned teenage girl who had supposedly already met a similar fate seven years ago in Santa Barbara.
Shawn and Gus receive a mysterious email asking them to come to a Cinnamon Festival in Dual Spires, a town so small it's written in parenthesis on the map. After meeting many of the colorful residents, including Robert Barker (Dana Ashbrook) and his wife Michelle who run the local diner and Sheriff Johnson, who questions how they heard about the Festival since they deliberately keep it simple in their town, they make their way to the square where the Festival is being held. But just after eighteen-year-old Randy is crowned Cinnamon King, Jack, a weeping teenager on a bike crashes the festivities and whispers upsetting news to the Sheriff. Robert and Michelle fear the worst has come true - their missing niece Paula has been found dead. Jack leads them all to the body, where Doc Gooden suspects she took her usual night swim and hit her head on a rock. Just then, Shawn receives another anonymous email suggesting it was murder.
After Paula's body is removed, Shawn learns Paula was originally from Santa Barbara and calls Juliet to fill her in. He then gets another email containing a long number with letters at the end, which sends them to the Doc's office for more answers. Doc Gooden, who was also Paula's therapist, hints that Paula was unhappy and might have killed herself. Shawn notices half a pair of earrings among Paula's personal effects and remembers seeing Randy wearing the other half at the Festival. They track Randy down to discover that he is the son of Sheriff Jackson, who Shawn notices is taking medication for something. Randy confesses that he was seeing Paula but they kept it secret because she was different than everyone else and it was complicated. He tells them he was at the library when Paula died and they leave to confirm his alibi. The librarian, Maudette Hornsby (Sherilyn Fenn), confirms this story, telling them Randy is there a lot and they have a special bond. Shawn realizes the numbers and letters from the email correspond to a book location, using the Dewey Decimal system, and they track it to find a book on reincarnation and rebirth. Shawn then calls Juliet who tells them Paula Merral drowned seven years ago in Santa Barbara.
Lassiter and Juliet come to Dual Spires and tell Shawn and Gus that Paula's body was never found the first time. Shawn realizes that Robert staged her earlier death. Robert confesses Paula's mother was abusive and it was the only way they could save her. He also admits that he's Paula's real father. Shawn finds Paula's diary which is partly written in Latin. He calls Father Westley (Ray Wise), who translates the passage and tells them she was seeing someone with the first initial "J." There's more but Shawn hangs up before he can hear the rest. Shawn realizes that the "J" stands for Jack, the weeping teenager. Jack tells them he dated Paula before Randy. He was with her that night just talking but he was hit over the head and when he woke, she was gone. Shawn knows Jack is a photographer, so he checks the roll Jack took that day and sees an angry Randy in the background. They track Randy down who confesses he hit Jack, but then Paula was mad at him so he went to the library like he said. He also confesses he used to date Maudette, which leads Shawn and Gus to now suspect her, but when they get to the library, they find Maudette has hung herself. They also discover a small room and evidence that it was her who had been sending the emails. The real killer would not have invited a detective to town. They notice smoke coming into the room and find themselves trapped until Father Westley saves them. Robert then picks them up and brings them to a lodge where he hopes they'll be safe. Shawn then puts it all together. Randy was the last hope for the survival of the town's idyllic way of life. The Sheriff is dying and Doc Gooden doesn't have any children. Paula was a threat since she had convinced Randy to leave town with her and see the world, so she had to be eliminated. The Sheriff and the doctor arrive and hold them at gunpoint, but Lassiter, Juliet and Jack show up in the nick of time and save them - Westley having translated the rest of the passage and realizing they were in danger. In the end, Shawn and Juliet try to grab a quiet moment at the diner but look around at the weirdness of the town and decide to get out while they can.
- This episode is the series' homage to Twin Peaks and therefore synonymously named.
- There are also several Twin Peaks actors that make an appearance in this episode: Dana Ashbrook, Sherilyn Fenn, Ray Wise, Sheryl Lee, Catherine E. Coulson, Robyn Lively, and Lenny von Dohlen.
- In another parallel to Twin Peaks, the question "Who killed Paula Merral" is emailed to Shawn. 'Paula Merral' is an anagram of 'Laura Palmer.'
- The theme to this episode was performed by Julee Cruise, the performer of the Twin Peaks theme song called Falling. The episode also ends on Julee Cruise's song Kool Kat Walk, which has lyrics written by Twin Peaks creator David Lynch.
- James Roday chose this as his favorite episode for USA Network's "Psych All-Night" event on March 21, 2014. It aired as fifth of six.
The list of references to pop culture and other media from this episode can be found here.