In 1990 Shawn and Gus are being cornered by a bunch of bullies. Shawn gets Gus to go up for him and defend them or fight the bullies off.
Shawn and Gus are in the middle of arguing over who will fire their freshly hired office assistant, Ken. Shawn and Gus thought they would have a heavier caseload ever since Henry was hired back at SBPD, but sadly, that didn't end up being true, so as a result Ken had to go.
During a parade in Santa Barbara's Chinatown, an important man named Mr. Arthur Chiang is being interviewed by the media when suddenly, a lone ninja dressed all in black somersaults into the festivities unnoticed. He then sneaks up behind Chiang's daughter and before everyone knows it, she's gone.
Back at SBPD, Mr. Chiang is in the Chief's office just as Shawn and Gus arrive hoping to get in on the kidnapping case. The Chief reminds Shawn that she never called him, but he protests: "the case called him." As usual, Shawn talks his way onto the case, and shortly thereafter they leave to go investigate the kidnapped girl's apartment. Shawn theorizes that the victim is hiding something. He then finds a hidden compartment in her desk containing a necklace. Instead of taking this piece of evidence straight to Lassiter like they are supposed to, Shawn and Gus take it to Juliet who has since taken a desk job at City Hall to take time to heal from post traumatic stress the Yin/Yang case brought on.
Juliet is hesitant to help, but can't refuse once Shawn piques her interest. She tells the guys that the evidence they found in the daughter's apartment is a Hong Kong 50-cent piece from the 1978 dynasty - and it's counterfeit. Just then, Shawn and Gus catch Lassiter coming into City Hall. Shawn shares the information about the 50-cent piece with Lassiter and immediately thereafter, Lassiter postures that this could have something to do with Triads being involved and mentions two rival Triad gangs: the Dragon Triads and the Golden Triads. He warns Shawn and Gus to stay far away from the Triads, as they are extremely dangerous.
Shawn and Gus don't listen to Lassiter's warning and immediately go to their former assistant Ken, who happens to be Asian, to get more information. At Ken's house, Shawn draws a symbol he saw that may be a clue. Ken tells Shawn that he likely saw the symbol spray painted on the outside of a certain martial arts studio.
Shawn and Gus are parked outside the martial arts studio Ken led them to. Suddenly, Gus spots the kidnapper breaking into the window above the studio. The two follow him by crashing through a window on the bottom floor. Shawn notices the same dragon symbol from the studio's sign tattooed on the kidnapper's hand. Shawn and Gus see the kidnapper right before he escapes out the back. They try to follow the kidnapper and eventually trail him to an apartment building where they see the jacket of the missing girl through a crack in a door. Shawn bursts through the door and is immediately met with the image of the kidnapper kissing his supposed victim.
Sang Tan, the supposed kidnapper and Becky, the supposed kidnapped daughter, reveal to Shawn and Gus that their fathers are the leader of the Dragon Triads and the Golden Triads respectively. When their relationship was discovered they had to run away instead of face their parents. Also, Becky's pregnant so Sang Tan wants to secure them money before a gang war breaks out between their families.
Back at SBPD, Shawn is telling the Chief that there was no kidnapping. So Shawn and Gus lead the Chief, Lassiter, and Henry back to Becky and Sang Tan's apartment to prove his theory. Lassiter finds a possible clue: blood on the couch. But Henry tells Shawn he thinks that Bekki and Sang played him. But Shawn disagrees.
Shawn, with Gus in tow, returns to City Hall hoping Juliet will back up his theory. She tells Shawn and Gus that there are two Tan sons: Teno Tan and Sang Tan. She also tells them that Teno has a history of starting trouble between the two gangs. Shawn quickly puts everything together. He claims that Teno is the real kidnapper, saying Teno wanted to take the inheritance of the gang away from his all too reasonable brother Sang.
Shawn and Gus take matters into their own hands by paying a visit to the leader of the Dragon Triad in hopes he will tell them about Teno's plans to start a gang war. Mr. Tan doesn't want to get involved in this business because he knows the feud will never end if he does. Shawn steps up, declaring that he will be the one to head to Teno's headquarters to set matters straight. Shawn and Teno end up getting into a ninja style brawl, Shawn obviously being the weaker of the two. Just as Shawn is about to lose all hope in the fight, Juliet shows up just in time and arrests Teno. Shawn is relieved, and Juliet thanks Shawn for helping encourage her to get back out in the field.
There is the evident Shakespearean reference, as well as the involvement of Detective O'Hara, in the title.
The gallery for Romeo and Juliet and Juliet can be found here.