- The Cameo: There's a cameo by the Fireflash, from the first episode. It consists entirely of Stock Footage from that episode, and seems to be mainly there for Padding.
- The Casino: where the episode starts and ends.
- Collector of the Strange: Dandridge has a strange obsession with gazelles. He named his company "Gazelle corp" and themed his entire office after gazelles. Nobody bats an eye at this.
- Composite Character: - Braquasso is basically George Bracque and Pablo Picasso merged into a single artist. Both were hugely influential before World War One, though, as they developed Cubism pretty much single-handedly.
- Cross Dressing Voice: Ray Barrett is having the time of his life as the Duchess. Recording sessions for this episode were reportedly hilarious.
- Drill Tank: The Mole's third appearance.
- The Gambling Addict: The Duchess.
- Here We Go Again: The Duchess has learned nothing from her mistakes and ends the episode once more in a casino.
- Large Ham: The Duchess. Not only is her puppet one of the most charicatured in the series, Ray Barrett is having WAY too much fun doing her voice.
- Machine Monotone: The Lift in the building of the buyer basically sounds like a non-malicious Dalek (voiced by the same guy, too). With a twist, in that machines were totally not expected to be able to reciprocate pleasantries. In a sense it is still impressive when one considers the necessities for processing the vocal input.
- MacGuffin: The Portrait of a Gazelle, that the bad guys want to get their hands on and which is the only object of value that the Dutchess has left after her disastrous evening at the Casino.
- Mythology Gag: A rather odd one: there is mention of a racehorse named "Desperate Intruder", the title of a previous Thunderbirds episode.
- Properly Paranoid: Lady Penelope worries that the Duchess' troubles aren't over yet when she departs for New York with her painting, and decides to keep a close eye on her. Her suspicions turn out to be correct.
- The Dutchess herself also took precautions, by hiding the real painting in her umbrella and putting a reproduction in her luggage.
- Tracking Device: Lady Penelope uses one to keep track of the dutchess during her trip to New York. This turns out to be a good thing since she is abducted.
Recap / Thunderbirds S 1 E 21 The Duchess Assignment
The One with... the Pythonesque lady.When the elderly Duchess of Royston loses everything at a casino in Monte Carlo, her friend Lady Penelope decides to help her. Enlisting Jeff Tracy's extensive contacts, Lady Penelope finds someone interested in purchasing the Duchess' last asset - Braquasso's "Portrait of a Gazelle". However, two crooks working for the crime syndicate responsible for swindling the Duchess at Monte Carlo kidnap the embattled aristocrat and make off with the painting, leaving her in a deserted house that is leaking gas. Can International Rescue save the Duchess before she falls victim to the ensuing inferno?