James Roday and Dule Hill (daemonstv.com)

Sounds dark and dramatic, right?  Not in the slightest.

"Psych" has an uncanny way of turning twisted, murderous storylines into a light-hearted comedy hour. Shawn and Gus bumble their way through serious detective work, always cracking jokes and making fools of themselves. It’s a mix of smarts and silliness that gets the cases solved... and keeps the audience entertained.

"Shawn, Interrupted" began with Lassiter throwing himself a congratulatory party (he's so humble) for solving a high-profile murder case. As the partygoers watch a TV broadcast on the crime Lassiter solved, breaking news hits--the accused killer, billionaire Bernie Bethel (Brad Dourif), is found not guilty due to insanity. The police department is convinced that he's not really crazy and is only faking it to keep out of prison.

To get proof that Bethel isn't insane, Shawn and Gus go undercover at the local mental hospital as a patient and guard, respectively. The hospital's Chief of Staff, Dr. Elliot, tells Shawn to pretend to have "narcissistic personality disorder"--something that's clearly not a stretch for Shawn, as everyone jokingly points out. He plays up his role to the max. In group sessions with the other patients, he has a blast throwing fake temper tantrums, picking fights, acting egotistical and pretending to have magic, psychic powers (albeit, he's done the last one for the past six seasons).

Meanwhile, Gus is even further off the deep end. He falls for a gorgeous patient named Vivian, who seems perfect--until she turns into a man. Vivian has multiple personality disorder (think United States of Tara) and flip-flops between "Vivian", her normal self, and "Frank", a middle-aged Gulf War veteran. Of course, Gus is blinded by her beauty and pursues Vivian/Frank anyway--which makes us think maybe he needs some time in a psych ward.

Shawn and Gus keep an eye on Bethel, waiting for his crazy act to crack, but as time goes on, they begin to realize that he is legitimately insane. They also discover that Bethel has severe arthritis in his left hand, which means he couldn't possibly have strangled his girlfriend to death and must be innocent.

With some good detective work, Shawn and Gus discover the real killer: Bethel's younger brother. In Bethel's insane state, his brother wanted to get power of attorney, and killed Bethel's girlfriend when she found out what he was up to. He was also was in cohorts with Lavender (guest star Molly Ringwald), one of the nurses at the hospital. Lavender gave Bethel medication that made him crazier so that no one would suspect he was faking it, keeping the real story of the murder under wraps.

Despite great performances by Dule Hill and James Roday this week, it was a huge downer that Ringwald was so underutilized. She only had about two minutes of screen time and never had a chance to really sparkle.

Next week: the one and only William Shatner guest stars as Juliet's father, who, despite his daughter's moral compass, has a seedy past as a con-man.

"Psych" airs Wednesdays at 10 PM on USA.

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