The Doctor breezes into a Greasy Spoon in 1950s New Mexico, in search of some quality junk food. Behind the counter of this one is Georgia Moffett, sporting a surprisingly good American accent; in front of the counter is Jimmy Stalkingwolf, a Stereotypical Native American; and on the counter is a weird glowy thing, left over from a flying saucer crash a few years ago.
This should end well.
Within minutes, they've been spotted by a Viperox battle drone, nearly captured by a Man in Black, and then really captured by Colonel Stark and the rest of The Army, and taken to Area 51, a.k.a. Dreamland, a.k.a. the Secret Government Warehouse full of cool alien stuff.
Less cool and more horrible is an actual alien, a live one, being held prisoner in the Elaborate Underground Base ever since her spaceship crashed several years before. Our Heroes don't get a chance to do much more than wave at her before they're bustled off to have their memories wiped, but the Doctor makes a mental note on his to-do list.
So once they've escaped, Jimmy Stalkingwolf takes them to see his grandpa, Night Eagle, only to get captured by The Men in Black actually Robots in Black and get saved by Night Eagle and his buddies, who take out the robots using bows and arrows, of all things. Night Eagle and friends are keeping another alien, of the same race as the Army's, in hiding. He's the husband of the first one, the one being kept prisoner in Dreamland, and he knows that the cool glowy thing in Cassie's diner isn't benign: it's a genocide bomb.
- Action Prologue: Begins with an alien ship being pursued and attacked, crashing into the New Mexico Desert in 1947.
- Always Chaotic Evil: The Viperox are your typical Scary Dogmatic Aliens intent on destroying all in their path... but the Doctor reveals they are still evolving, and by a future miracle will become more peaceful.
- Anime Hair: The Tenth Doctor's already distinctive gelled hair is taken Up to Eleven.
- Apocalypse How: From the sounds of it, the Viperox inflict a Class 2 on every world they successfully conquer (possibly a Class 4 in terms of the non-sapient biosphere). The Doctor states the Viperox "savage and decimate" every attacked world, but also that there's a good chance that there could well be something (if not much) left of the Gray aliens' homeworld for them to live on and salvage after the Viperox attacked it. The Viperox's plan is to "tear [planet Earth] to shreds" for humanity as soon as their Teeth-Clenched Teamwork is at an end.
- Area 51: A.k.a. Dreamland.
- Artistic License Geography: This anachronistic sign◊ from the establishing shot of the first episode places Interstate 25 within 35 miles (36 kilometres, for the rest of the world) of Roswell, when Interstates didn't exist yet, and I-25, when built, would be more than 100 miles (160 kilometres) west of Roswell at its closest point.
- Attack Drone: The Viperox.
- The Big Board: Complete with the Soviet Union marked in red with a Hammer and Sickle (subtlety never really worked in Doctor Who).
- Big Damn Heroes: Thanks to Night Eagle's Improbable Aiming Skills.
- Bowdlerise: Colonel Stark's unsubtle line about the only cure for a communist being a bullet is usually cut out of reruns.
- The Brigadier: Stark (after a spell as Colonel Ripper).
- Bug War: The Greys are at war with the insectoid Viperox.
- Cliffhanger: Being broadcast in 7-10 minute parts does that.
- Captured Super-Entity: The alien at Area 51.
- Continuity Nod: The Sarah Jane Adventures has made a few references to this episode. Androvax has a ship based on blueprints from the Roswell crash, and the Alliance of Shades themselves appear in the series four story "The Vault of Secrets".
- Eagleland: America (especially the military) is painted in a negative light.
- E.T. Gave Us Wi-Fi: The amnesia gas is extraterrestrial.
- Evil Brit: Lord Azlok is the only other character in all 6 episodes to have a British accent.
- Explosive Breeders: The Viperox don't transport an invasion force to a targeted world...The Doctor: They land, go underground and hatch one.
- Foreshadowing: Another hint is dropped of the Doctor's impending fate."Your day will come, Doctor!"
- Genetic Engineering Is the New Nuke: Weaponised version.
- Giant Flyer: The Viperox have wings and can fly.
- The Greys: The captured alien and her husband.
- HeelRace Turn: The Doctor states the Viperox will one day make this and become peace-loving, suggesting he knows from seeing the future, and it's part of his justification for actively avoiding inflicting the Viperox's total extinction.
- Idiot Ball: The soldiers never confiscate the sonic screwdriver even after the Doctor uses it to escape multiple times.
- Immune to Bullets: The Viperox continue this great Doctor Who tradition.
- Improbable Aiming Skills: Possessed by Night Eagle.
- Ink-Suit Actor: Georgia Moffett's character Cassie.
- Magical Native American: Borderline example in practice but definitely in spirit.
- The Men in Black: Robot Men in Black with Sinister Shades. (It is even lampshaded that their organisation is called the Alliance of Shades.)
- Names to Run Away from Really Fast: The head Alliance of Shades agent introduces himself as Mr Dread. The Doctor quips that the others must be Mr Fear, Mr Terror and Mr Apprehension.
- Pungeon Master: The Doctor gets in a particularly groan-worthy one after escaping the warehouse in a crate.
- Take That!: Briefly touched on in a very bitter, but thankfully not-long statement by Jimmy in regards to the army. Specifically, that the US military can do whatever it wants if it's deemed necessary, and has been doing so since the infamous Bear River Massacre (one of the very many less-than-redeemable behaviours of US expansionism against the American Indians).
- Wasteland Elder: Night Eagle, Jimmy Stalkingwolf's grandfather.
- Xenomorph Xerox: The Viperox Queen has a similar look and posture to Alien Queen from Aliens.
- You're Insane!: Lord Azlok's response to the Doctor insisting the Viperox will one day become a peaceful species is to derisively call his assertion madness.