"Lost Kingdom" is the eight episode of the second season of Thunderbirds Are Go!, which was broadcast on December 3, 2016.
After a seaquake near the coast of Greece reveals the lost city of Atlantis, Francois Lemaire ignores International Rescue's warning about aftershocks and with his wife, Madeline, venture below the depths to explore the area. When their submarine becomes stuck, Virgil and Gordon are called to assist. Brains and MAX go with them so that they could see the Solar Kythera, an ancient device used to view the stars.
- Scott Tracy, Alan Tracy: Rasmus Hardiker
- Virgil Tracy, Gordon Tracy: David Menkin
- John Tracy: Thomas Brodie-Sangster
- Kayo: Angel Coulby
- Brains: Kayvan Novak
- Lady Penelope Creighton-Ward: Rosamund Pike
- Parker: David Graham
- Grandma Tracy: Sandra Dickinson
International Rescue Equipment UsedEdit
Non-International Rescue Equipment UsedEdit
- The Jules Verne
- The existence of Lost Kingdom was revealed on the 6th May, 2016 via official set pictures on the Thunderbirds Are Go! social media network.
- The Lemaire's submarine is named after the famous author Jules Verne, who wrote Twenty Thousand Leagues Under the Sea and Journey to the Center of the Earth.
- The 'Solar Kythera' is named after the Antikythera mechanism, an ancient astronomical device found in a shipwreck near the Greek island of Antikythera.
- The probe launched from Thunderbird 5 is the Stealth Mine from Space Race.