A hanging body is found that looks shockingly similar to Lanie, and later another is found that's shockingly similar to Esposito. Their cases point to Dr. Kelly Nieman, a plastic surgeon who may have a history with one of Castle's greatest foes.
- The Bad Guy Wins: Jerry Tyson and Kelly Nieman get away with everything they want.
- Hidden in Plain Sight: The killer turns out to have been the security guard who discovered the Lanie lookalike.
- No One Could Survive That!: Almost quoted verbatim by Beckett when she expresses doubt that Jerry Tyson could have survived a 100-foot drop into the river. The more Genre Savvy Castle, knowing that the NYPD Never Found the Body, remains skeptical about Tyson's death, and is soon proven right when they discover that the 3XK case files have all gone missing.
- The Ghost: While 3XK was behind the plot to use the duplicates to steal or destroy all his police records, the actual killings of the doppelgängers were performed by one of his accomplices and the man himself never shows up.
- Soundtrack Dissonance: The music played at the end (Vera Lynn's "We'll Meet Again") is very cheery compared to the rest of the episode. This is deliberate as it's a threat 3XK will return.
- You Have Outlived Your Usefulness: The victims were made to look and sound like Lanie and Esposito for the purpose of stealing or deleting all police records related to 3XK, and were killed shortly after the task was completed.
