 Jeff Tracy is driving Brains up the wall by demanding he design a spectacular new rescue vehicle, a Thunderbird 6, and then constantly rejecting all his efforts. Still, at least Brains got further with an airline company when he designed a revolutionary airship for them. Lady Penelope and some of the International Rescue crew are the honoured guests on the maiden round-the-world flight but sinister forces are at work and a plan is put into action that may leave Jeff with only his brand-new Thunderbird 6. If he evers accepts one of Brain s designs, that is.