Daniel loved this episode. He wanted to know what was going on all the way through it. It begins with a huge, over-elaborate truck shipping some mysterious cargo and he just had to know what was in the box, what was in the box, what was in the box. A replacement Angel fighter jet was in it, and once three are all parked in a remote facility, Captain Black burns it to the ground, leaving three duplicate jets in Mysteron control.
This is apparently one of the best-remembered episodes of the series. Almost the entire second half is given over to a dogfight, with Harmony, Melody, and Rhapsody gunning after the three duplicate fighter planes. Captains Scarlet and Blue spend the entire sequence under cover in a trench with Destiny, but that’s irrelevant to the edge-of-your seat thrills of the dogfight.
Daniel spent the sequence wide-eyed and making missile sound effects of his own, loving this completely. If the objective was to blow the minds of any four year-olds watching, Gerry Anderson’s team totally succeeded.