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"I have made my reputation by keeping secrets - and that includes your uncle, Ms. Kyrano."

"Undercover" is the 25th episode of Thunderbirds Are Go!, and was broadcast on Saturday, January 16th, 2016.


At a hangar in an airport, a black arms dealer called Banino meets with Parker and Lady Penelope who were impersonating a man called Mr Mendocia and his assistant. The operation is watched by Kayo, Colonel Casey and the GDF from their control centre and an aerial transporter above the hangar. Inside the hangar, Parker shows Banino a collection of gold lidium before the dealer shows him a Repulsor Magnet Array, a powerful supermagnet stolen from Houseman Industries. At the GDF control centre, Ned Tedford arrives with a plate of food but accidentally puts it on a button, causing the soldiers inside the GDF flyer to drop into the hangar. Banino uses the magnet to attack the troops and escapes with Parker, the repulsor and the lidum in the flyer.

Kayo pursues the flyer in Thunderbird Shadow but Banino uses the flyer’s missiles to ward her off. Despite Kayo’s objections, Scott who was watching the operation from Tracy Island heads to the scene in Thunderbird 1. On the flyer, Banino smashes the controls with the repulsor’s case before bailing out in a hang glider with Kayo in pursuit. In FAB 1, Lady Penelope contacts Parker to land the plane at a nearby factory but the weight of the plane causes the roof to collapse. While the workers evacuate, Penelope breaks into the plane to save Parker while Scott rescues the lone worker remaining in the factory.

Meanwhile, Kayo encounters Banino and demands the repulsor and the lidium but it turns out the repulsor was missing due to Parker snatching it while hugging Banino on the plane earlier. Banino shows a photo of her and the Hood before fleeing. Back at the Factory, Parker saves Penelope by using the repulsor to stop the plane from crashing on top of them before breaking out. Kayo tells Scott and the others about Baninos escape before saying she will tell her secrets to the rest of the Tracys back home.



Scott: "International Rescue isn't usually in the bad guy business. But once Parker heard there was a role in it for him, I couldn't stop him. Let's just call this an experiment and experiments always make me nervous."

Scott: "Thunderbirds are rescue vehicles. They're not meant for aerial dog fights."
Kayo: "Well, sometimes rescuing people requires a little dog fighting."

Parker: "I always say, hugs are the answer to all of life's problems."
Lady Penelope: "Old habits die hard."
Parker: "Yes, m'lady."

International Rescue Equipment Used

Non-International Rescue Equipment Used



  • A Fireflash airliner makes a short cameo at the start of the episode.
  • Houseman Industries is a reference to End Of The Road.
  • This episode returns to the subplot of Touch And Go, with Kayo and Scott debating International Rescue's role as law enforcement.
  • Ned Tedford and his plant Gladys return in this episode.
    • The notion of Ned being sent to the GDF North Pole base when he thinks he will be "safe" there is a foreshadow of him being in danger again in Up from the Depths Part 2.
    • Ned later worked in the North Pole GDF Seed Vault in Growing Pains.
  • Kyrano is mentioned in this episode for the first time in the series.
  • The first episode we see that FAB 1 can go 'undercover' by changing colour to black. This can also be seen in City Under the Sea.
  • The plate number of FAB 1 'undercover' (A21384), is a reference to Commander Strakers Car from Gerry Andersons series 'UFO'.
  • This episode is directed by newcomer Tim Gaul.
  • Kayo decides to finally tell the truth about her and her Uncle.
  • This is the first episode to just feature one Tracy.
  • This is the first time to see Parker in an outfit other than his black one.


  • When Kayo's bike docks with Thunderbird Shadow the rear of the cockpit does not slide back and lock into place like in previous episodes when this is shown.
  • The close up of Kayo's hologram while talking to Scott as she is being fired at by missiles has the background in reverse, yet Kayo's Hologram is still coming from its proper location.

Foreign Titles

  • Dutch: Geheime operatie (Covert Operation)
  • French: Sous couverture
  • Spanish: Encubierto