After a young ballerina, who moonlights as an exotic dancer, is murdered following a confrontation outside the club where she works, the man waiting for her outside becomes the main suspect. However, his motivations for wanting to speak with her don't naturally lead to murder. Also, something about how the body had been treated suggests to Goren that this wasn't necessarily done out of anger.
What makes this such a great episode isn't the mystery. It quickly becomes apparent that John, a shy candy maker played by Neil Patrick Harris, is the culprit. What's so fascinating is the vulnerability with which he plays the character and Goren's attempt to understand him.
The final twist, though shocking, has nothing to do with a last-minute reveal. Instead, it sees Goren turning his back on his partner and superiors to do what he believes is right. It's a moral dilemma that asks the audience to think about what they would have done in his situation, rather than beating them over the head with an obvious message.