The moonlanding was fake. The astronauts thought they went to the moon only because aliens abducted them and brought them to Mars instead. The memory wipe cause them to hallucinate and think they visited the moon!
The foreshadowy thing in Langdon's rear view mirror was a dog.
"Here we are, at Teabag's house!" said Langdon "Teabag is his nickname. It comes from the British pastime of tea parties and not from the American pastime of putting your balls on someone's face."
"Yee haw!" said Thegirl.
"Also, Its possible he's a villain."
"Well slap my butt and call me a dirty ho!" Thegirl replied in Americanese."
As they entered the big ass mansion, Langdon and Thegirl saw an old guy dressed in Ritz. We was also wearing Cheezewiz and clothing.
"You buggerin' yanks just interrupted a jolly good consumation of the bleeding good snack items my good fellow chap cheerio!"
"He says 'y'all interuptin' muh supper!'" Thegirl translated.
"We need to learn THE CODE."
"I got me a blimey good Da Vinci piece that'll show you bent bugger fish and chips lift bullocks!"
"He says 'he got a purdy drawin' from a cowpoke named Leonardo Da Vinci'."
"Lets see it, so I can know THE CODE!" Langdon said. They walked down the hall and came to The Last Supper. It was the real one. Like really real! Holy crap! This guy's freaking loaded. Well what do you expect of a guy who's got a big ass mansion?
"Look at this!" said Teabag. "Now with new technology we can look at the under layers of a painting to see what kind of embarrassing mistakes the artist made! Fit Bird, bloody twat!"
"He says take a looksee at this tootin' thang, partner!"
Teabag operated his X-Ray machine and sure enough, you can see the under layers.
"But Leonardo Da Vinci makes no mistakes! He is God! No he actually knew that this technology would exist someday and hid clues under the top layer. Behold that guy looks like a chick! Bugger Wank!"
"He says..."
"Oh shut up! I know what he means!" said Langdon.
The guy in the painting did look like a chick. There was also a comic book style word balloon that said "clubs secret join to fun its!"
"What could it mean!" said Thegirl.
"No one could decipher that CODE!" said Langdon.
"Thanks for coming over!" said Teabag. "I have no friends, so the only people who visit me are my adoptive kids, Edward and Alice. Here's a present." The old guy gave Langdon and Thegirl a Macguffin and wished them a safe journey. Next stop: THE CODE!