Undercover is an episode of Thomas' Adventures of Thunderbirds Are Go ( 2015 TV Series).
An undercover operation involving Lady Penelope and Parker to recover a stolen Repulser Magnetic Array for the Global Defence Force gets blown prematurely. Parker is taken prisoner by the thief aboard a stolen GDF flyer, with Kayo in pursuit in Thunderbird Shadow. The flyer crash lands on a factory roof and International Rescue and the Steam Team must intervene to help save Parker and a factory worker. Kayo confronts the thief to find he knows her secret relationship with the Hood, and must weigh letting him escape against her secret coming out in the open.