Gordon returns from his assignment in Washington, D.C., accompanied by Rosa Montebello, an Italian opera singer. That evening she is attacked while appearing on-stage in Lucia di Lammermoor. The culprits appear to be a mysterious society known as the Order of Lucia. What is behind this attack? What happened to the three other divas who, over the last five years, have disappeared after singing the role of Lucia - women whose ghosts are now said to haunt the opera house? And what's the connection to Karl Crenshaw, the reclusive brother of Max Crenshaw, wealthy opera aficionado?
Tropes present in this episode:
- The Cast Showoff: Patrice Munsel (Rosa Montebello) isn't just playing at being a coloratura soprano — for many years, she was one. At 18 she became the youngest singer who ever starred at the Metropolitan Opera and went on to perform there 225 times.
- Designated Girl Fight: Collingwood and Karl Crenshaw are paired up during the climactic fight scene. At first it doesn't appear to be this trope, but then the mask comes off...
- Dramatic Unmask: At the end, to reveal that "Karl Crenshaw" is actually Caroline Mason, whose voice was irreparably damaged in the fire that supposedly killed her.
- Faking the Dead: Caroline Mason. The body identified as hers was actually her maid's.
- Got Volunteered: How Ellen Collingwood ends up posing as Rosa Montebello.Collingwood: "Oh, now wait a minute, Mr. Gordon...."
Artie: "You said yourself it was a brilliant idea, Miss Collingwood."
Collingwood: "Mr. Gordon..."
Artie: "And I have no other alternatives, you remember that?"
Collingwood: "But Mr. Gordon, you must remember that my duties with the Secret Service do not include my jeopardizing my..."
Artie: "Thank you, Miss Collingwood, thank you for volunteering."
- It's Always Mardi Gras in New Orleans: For once, averted (ironically given that the villain in the episode is masked).
- Karma Houdini: Rosa Montebello, an unrepentant snob who treats Artie like dirt for no reason at all and is generally so unpleasant that the episode's actual villain (an Expy of The Phantom of the Opera intent on kidnapping her to go with two other opera singers (s)he's abducted) is far more sympathetic (which may well have been the intention of writers Ken Pettus and Alf Harris, given the climax). She never gets her comeuppance. Or, for that matter, kidnapped.
- Love Makes You Crazy: The reason behind Caroline Mason's abduction and imprisonment of other coloraturas. Without her voice, she knew she was only "half a woman" to the man she loved; for his sake she was trying to recreate that voice in another.
- The Not-Love Interest: A young, beautiful secretary, Miss Ellen Collingwood, is introduced early on in the episode. She's very friendly, very helpful, Jim and Artie both seem to like her — pretty much your typical Girl of the Week... except that she apparently doesn't end up romantically involved with either of the agents. On a show which makes a point of at least briefly pairing up every attractive female, attached or otherwise, with one of the leads, this is an earth-shattering (non-)event.
- Pretty in Mink: To a party, Rosa wears a cape trimmed with white fur.
- The Prima Donna: Ms. Montebello. Gracious and charming to those who fawn over her, indulge her whims and/or share her disdain for everyone not of the upper-classes; rude, spiteful and insulting - often at the top of her voice - otherwise. However, her reputation as a first-class coloratura appears to be well-deserved.
- Reality Subtext: The reunion scene on the train between Jim and Artie marks both the latter's return from a long assignment in D. C. and Ross Martin's return from a long but successful recovery period after a near-fatal heart attack.
- Stealth Insult: Artie takes advantage of his disguise as Colonel Vladislaw to tell Rosa Montebello exactly what he thinks of her. She, of course, is totally oblivious."Vladislaw": "But just a short while ago I had occasion to be with... well, a world-renowned coloratura, and indeed I found her to be vain, rude, arrogant, shrewish... oh, completely the opposite of what you are, dear lady."