A very long two-parter Series episode by Doctor What and Dave Howery, their first collaboration. The full thing came to 25,000 words. The episode features many film references and parodies, most obviously Mad Max.
The AH.com Ship shifts into a timeline above a desolate post-apocalyptic desert Earth, but almost immediately hits a spaceborne minefield around the planet. The ship is damaged and crashes. The crew is unhurt, but the ship needs replacement parts before it can take off again - and somehow they have to neutralise the minefield.
They are attacked by a tribe of sand-pirate scavengers, the Snakes, led by “Lord Enormous Guy”, who want to capture the ship for parts and supplies. The AH.commers beat them back and then a survey team encounters a more peaceful tribe, the Sandkats. They learn that the entire population of the planet consists of luakel clones, but all of them are defective or deformed in some way. luakel himself is treated as 'the Chosen One' by the Sandkats. The Snakes try to break through the AH.com's armour using trebuchets, but are thwarted by the survey team allied with the Sandkats.
In the second part of the episode, the Sandkats tell the AH.commers about a supply dump from which they can get the parts and supplies they need. The AH.commers go there and find what they need, but halfway through the Snakes show up again and surround the compound. Matt finds an enormous artillery gun in the storehouse and immediately falls in love with it. The AH.commers also find a huge truck, which they load up with the supplies and gun. luakel is captured by yet another tribe, the underground-dwelling Morlocks, who have opposite beliefs to the Sandkats and try to sacrifice him as 'the Great Deceiver', but luakel is rescued. The AH.commers blast out of the compound in the huge truck, and an exciting shoot-out follows as the Snakes and Morlocks pursue in their own vehicles. The AH.commers emerge victorious and arrive back at the crashed ship.
The ship is repaired, and Matt uses the giant gun to shoot down all the satellites in orbit. He is distraught to learn they have to leave the gun behind, while Diamond has a brief, disturbing relationship with a female luakel called Slinky, with razor-sharp teeth. The AH.com blasts off from the planet and returns to the Hub, where luakel, Matt and Diamond all mope over what they've left behind. Doctor What has left his 'Big Busty Lesbians' magazine behind by accident, and it becomes the new holy tome for the Sandkats.
The episode was an adventure in itself, but also part of the 'luakel clones' story arc which also featured in “A SMALL PROBLEM”, “V IS FOR VENDETTA”, “THE MACHINE” and others. The Planet of the Luakels concept meant, as Dave pointed out, that he and Doctor What could have an episode with a large native-timeline cast without giving any n00bs cameos!