Welcome to the 1960s, where no one understand's Sam's 90s pop culture references, actual police boxes sit on the streets, and crazy people are running around in plant shops. Wait a minute, no. Even Sam can tell that last one isn't normal, and she fights aliens on a regular basis.
Sam and the Doctor go to investigate the nutjobs running around and are soon caught up in a psychological study of race memory that turns out to have been the result of (surprise!) alien activity. An average guy who works in a shop named Fitz Kreiner, who just happens to be the son of one of the crazies, asks Sam out on a date, but their date is ruined by someone getting murdered. Fitz is then blamed for the murder and goes on the run.
The alien incursion and death that surround the whole deal is same old, same old for the Doctor and Sam, but for Fitz it is both terrifying and hopeful. His boring life has suddenly become exciting like he's always wanted. If only he doesn't get killed by some monster or other before he has the chance to enjoy it.
Tropes present in The Taint include:
- All Germans Are Nazis: In-universe. Fitz's father was a German, and just after WWII, this didn't make him popular."My dad was a German. He wasn't a Nazi.""They're all Nazis," she snapped. "Everyone knows that."
- Aside Glance: Sam is so unimpressed with Fitz's flat that she forgets she's in a book.Sam looked wryly to an imaginary camera.
- Battleaxe Nurse: Nurse Bulwell, who despises her patients both individually and collectively.
- Catchphrase: Dr Roley is fond of the Minced Oath "Crikey Moses!"
- Cigarette of Anxiety: Fitz, after everything goes crazy at Bulwell's place.
- Determinator: Azoth"Azoth felt no fear at the prospect of nonoperation, only concern that he should not fail at his task."
- Everybody Smokes: In the 60s, much to Sam's shock and horror.
- Final Solution: Azoth's plan to destroy the Beast.
- Holding Both Sides of the Conversation: Fitz cleverly scares the two villains of the week away from Sam by hiding around a corner and putting on a number of voices to make it sound like he's ten guys who are all probably much tougher than he is himself and intent on clobbering said villains.
- Identical Grandson: Fitz's great-grandfather's Obliviously Evil twin is recognizably similar to Fitz himself: same long nose, straggly hair, and thin face and build. Fitz keeps finding him "infuriatingly familiar", and, unsettlingly, he has moments of acting like a Psychopathic Manchild version of Fitz.
- Obfuscating Disability: Fitz fakes a limp in the club where he plays to get sympathy.
- Organic Technology: The Benelisans used brains as computers
- Robotic Psychopath: Azoth was created to commit genocide against the Beast
- Shout-Out: To The Lord of the Rings:"Like something out of R.J. Tolkien"
- The Shrink: Charles Roley, an odd mix of "well-meaning but dopey" and Psycho Psychologist, who seems unsure himself how much he's trying to cure his patients based on his theory and how much he's just using them to test it.
- Title Drop: "Let us implement the program at a point before the Beast arrive here, so their taint will never be felt."
- Totally Radical: Sam, but in reverse, being a young person of the 90s attempting to use past lingo."I bet you were a real hip swinging cat, weren't you?"
