The Tardis lands on a desert-like planet. The Doctor, Steven and Vicki encounter a small robot, which Vicki dubs a Chumbley. The Chumbley is subsequently disabled by a group of patrolling Drahvians. The Drahvians, who come from the planet Drahvia in Galaxy 4, inform the time travelers that the Chumbleys are the robot servants of a race of aliens known as the Rills. The Drahvians and the Rill have been at war with each other for many years. The Drahvians' spaceship met a Rill spaceship just above this planet (which, we also learn, is also in Galaxy 4) and both shot each other down and crash landed here.
The planet will shortly be destroyed, and the Drahvian ship cannot be repaired. The Drahvians have placed their hopes on capturing the Rill ship, which they believe has been repaired. The Drahvians send The Doctor and Vicki to capture the Rill ship and defeat the Rills. Steven is held as a hostage to ensure compliance.
Steven attempts to escape, but gets trapped in an air lock with the air slowly being sucked out, trapped between the Drahvians in the ship and a Chumbley robot outside. Meanwhile, The Doctor and Vicki meet with the Rills and discover that the Rills have been and are willing to take the Drahvians with them on their ship. The Drahvians have refused the Rills' offer, preferring to remain in a state of war with the Rills.
The Doctor and Vicki, having learned the truth of the relationship between the Drahvians and the Rills return to the Drahvian spaceship and rescue Steven from the air lock. The three time travelers return to the Rill ship, which lacks enough power to effect a liftoff from the planet. The Doctor gives the Rill ship a jump start from the Tardis, and the Rills' ship takes off. The Rills leave a Chumbley robot to escort The Doctor and his companions back to the Tardis. The Drahvians, foiled in their attempts to capture the Rill ship as well as the Tardis, perish when the planet is destroyed.
Galaxy Four, for many years, was thought to be a completely missing, with the exception of a few clips. The third episode of this story, entitled Air Lock, was found recently and returned to the BBC archive. The special edition DVD of the Aztecs includes the recently found Air Lock, along with a telesnap reconstruction of the three missing episodes.
The reconstruction was pretty good, and a great way to frame the found episode Air Lock. It's great that we now have Air Lock in any case, since much of the third series/season (and the following fourth and fifth series/seasons) are missing. It's not often that Doctor Who fans get to see an episode of Doctor Who that hasn't been seen in decades and Air Lock definitely didn't disappoint.
The rest of the story doesn't disappoint, either. Galaxy 4 is one of those episodes where the moral is simply this, beware of appearances. The Drahvians look appealing to a human eye, since they are humanoid. However, their beauty is belied by their actions. The Drahvian's leader, Maaga, is cold and ruthless and reveals her true intentions when she attempts to kill Steven in the air lock. The Rills, despite being less appealing to the human eye, are by far the more sympathetic of the two alien races.
I know there were some complaints about releasing the Galaxy 4/Air Lock story as part of the Aztecs Special Edition DVD. I certainly understand those complaints, as I don't often buy the Special Edition DVDs myself, as I just can't justify re-buying material I already have. Perhaps the better way to look at it is this way: you're buying Galaxy 4, including the newly found Air Lock, and getting the Aztecs Special Edition as a bonus feature. I wouldn't hesitate is buying this, as I found Galaxy 4 well worth the price of admission.
