Eddie (Sam Rockwell) and Paul (Ben Schwartz) are two bumbling crooks out on parole, working at a crappy diner, when English lawyer Katherine Rookwook (Phoebe Fox) hires them to come to London and intercept a package in transit. Their efforts draw the ire of Arkady (Peter Polycarpou), a crime lord to whom Katherine is in debt, and his mulleted henchman Deacon Bradshaw (Peter Ferdinando). When the protagonists learn that Arkady is planning to steal a priceless diamond called the Blue Iguana, they team up with Katherine's cousin Tommy Tresham (Al Weaver) to stake out a pub owned by Deacon's mother Dawn (Amanda Donahoe) in the hopes of stealing the diamond and collecting the reward money themselves.
Blue Iguana contains examples of:
- Accent Interest: Dawn asks Paul to repeat the phrase "Yes, ma'am" because she finds his American accent sexy. Paul takes advantage of her attraction to Americans by pretending to be an astronaut named Teddy Roosevelt whose last girlfriend tragically dumped him while he was heroically saving the earth from an asteroid. Dawn eats it up.
- Bathroom Stall Graffiti: The men's room in the Bradshaw pub has a drawing on the wall of a shark giving a man a blowjob.
- Bitch Slap: Arkady repeatedly slaps Deacon in the face for his incompetence.
- Blackmail: At the beginning of the movie, Katherine threatens to expose Paul and Eddie's boss's shady business practices if he reports their unplanned vacation to London to their parole officers.
- Cut His Heart Out with a Spoon: Deacon comes up with individualized death threats for all the protagonists. He plans to stab Eddie's head until it explodes and then shoot him between the head, set Katherine's tits on fire with petrol, cut Tommy's balls off and staple them to his ears, turn Paul's dick into ravioli, and force Cornelius (Robin Hellier) to rape Paul with both his penis and a strap-on at once.
- The End: The last shot of the movie is of Eddie's favorite comic book, open to the last page, which shows the words "THE END."
- Fingore: Arkady cuts Deacon's right pinkie finger off while demanding to know the whereabouts of the diamond.
- Generation Xerox: Invoked by Deacon, who hero worships his dead father, to the point of copying his '80s Hair and wearing his denim jacket everywhere.
- Hostage Situation: When the protagonists steal the Blue Iguana, Eddie is shot in the leg and left behind. Arkady offers to release him in exchange for the diamond.
- Lens Flare: An in-universe example. Paul keeps planning to make a movie, which, as he excitedly describes, will have lots and lots of lens flare.
- Of Corpse He's Alive: Deacon murders Dawn in the car, then drives out of the parking lot with her corpse in the passenger seat. When the ticket guy peers suspiciously into the car, Deacon motions towards Dawn and mimes drinking from a wine bottle.
- Percussive Therapy: When Arkady informs Katherine that she must remain in his debt to save Eddie and Paul, she goes into the hallway, screams in frustration, and hits the wall with her purse.
- Rage-Breaking Point: Deacon finally gets sick of Dawn insulting him and his father and breaks her neck in the car.
- She Cleans Up Nicely: Katherine was cute to begin with, but when she wears more expensive clothes and lets her hair down, Eddie is so struck by the difference that opera music starts playing in the background.
- Stress Vomit: After Paul is covered in blood from the shooting of a henchman, he runs off to the bathroom, where he can be heard vomiting loudly. Later, when the rest of the group is covered in gore from Deacon's explosion, Eddie vomits in a sink.
- Umbrella Drink: Katherine sips a cocktail with an umbrella and a large slice of pineapple. After an argument with her, Paul steals the pineapple.