Thunderbird Six

It's the early twenty-first century. The work of International Rescue is highly secretive. Most of its work is based on Tracy Island in the Pacific. The Thunderbirds carry out most of the work led by ex-astronaut Jeff Tracy and his five sons - Scott, Virgil, Alan, Gordon and John - who fly Thunderbirds 1 through 5, aircraft each designed to carry out a different specialized function. The aircraft designer is code named Brains. Their one team member not based on the island is British Lady Penelope Creighton-Ward, who does most of her work in the mobile center coined Fab1, operated by her manservant, Parker. Brains, under the pseudonym Mister X, has just designed a new pleasure aircraft called Skyship One for New World Aircraft Corporation's holidaying division. Lady Penelope - with Parker and Fab1 by her side - and Alan have been invited to go on its maiden voyage, although Tin-Tin, the daughter of one of the Tracy's domestics and Alan's love interest, sneaks along as well. What they are unaware of is that Skyship One's crew members are not who they seem and plan to use Lady Penelope to ruin the Thunderbirds. Meanwhile, Jeff believes they require a Thunderbird 6, although he provides no specifications to Brains. A usually complacent Brains is uncharacteristically rattled when design after design is rejected.