The final episode of Thunderbirds is a Christmas special. It was not planned to be the series finale; work was stopped after the program’s paymaster, Lew Grade of ITC, admitted failure in selling Thunderbirds to one of the big three American networks. So they finished up the one they were making, shelved the scripts for future installments, and started looking into making feature films instead.
The only action of note in this story comes from a detailed heist, in which a pair of crooks digs into a vault to steal millions in gold. The floor is hair-trigger sensitive, so once they break through, they’re going back and forth on ropes and pulleys. It’s really fun, but the rest of the episode is pretty dull.
There is a strange little error in this one. Everything about the show’s publicity states that it is set in the 2060s, but there’s a calendar in the Tracys’ house that says it’s 2026.