When two episodes of The Invasion were lost (as was the case of dozens of stories from the original Doctor Who series) Cosgrove Hall came up with the idea to merge the existing audio (courtesy of fans who had kept recordings of the soundtrack) with brand new animation for the DVD release. Part 1 was watchable, although the old-fashioned technique occasionally slowed things down. Episode 4, the second missing chapter of The Invasion, suffers from the same problem, but remains a piece of enjoyable, if a bit dated, cult television.
Having managed to elude Vaughn's thugs, the Doctor and Jamie overhear a conversation regarding the whereabouts of Zoe and Isobel, and decide to rescue them with the help of UNIT. Meanwhile, Vaughn is desperate to capture the Doctor and know more about him, especially as whatever sinister plan the businessman was working on is about to be set in motion. Apparently, there might be a connection between the often mentioned invasion and a series of recent UFO sightings. Then again, with our favorite Time Lord around, it couldn't be a normal threat, could it?
The plot starts to become more interesting, as the mystery gets closer to a solution and the pace is raised a notch or two. Also better is the animation which, despite a few stiff bits, looks a bit slicker than it did in Ep. 1. One scene in particular benefits from the new format: a helicopter rescue sequence that wouldn't be half as good to look at had it been live-action, considering the budget for the show wasn't that conspicuous in 1968. That section is the real highlight of this chapter, alongside the mandatory cliffhanger ending that suggests The Invasion might finally be getting somewhere.