Double Caper

A Double Caper is a plot that takes the following form:

The protagonists are hired for The Caper.
After pulling it off, they learn that they were hired under false pretenses—they don't get paid, or their employer isn't who they thought, or the justification they were given for the theft turns out to be a lie.
They then pull another iteration of The Caper on their original employer, for vengeance and/or to get the stolen goods back to their rightful owner.

This is often used as a way to have a plot based on The Caper that has some degree of moral justifiability. It also provides a built-in structure for Up to Eleven in the execution of Caper #2.

Examples of Double Caper include:

Comic Books

In X-Men Noir: Mark of Cain, Thomas Halloway and his ersatz X-Men (Cyclops, Captain Logan, and Eugene Judd) are hired by Halloway's old father figure Cain Marko to steal the Crimson Gem of Cyttorak from a temple in Madripoor. When they deliver the gem, Marko double-crosses them; he payed them in newspaper. Thereafter, they don't go after Marko... but only because someone beat them to it. They decide to track down Marko's killer instead, reasoning that whoever did him in must now have the gem.

Film

The team in Sneakers is hired to steal an encryption device from a mathematician. Their employers claim to be NSA agents, and say that the mathematician is being funded by Russia. Actually, he's being funded by the NSA, and the employers work for The Syndicate.
The remake of The Italian Job has the crew pulling a caper against the guy who double-crossed them and took the gold from their original caper.
The Hot Rock did this to extremes.
The first Mission: Impossible starts with a caper that goes wrong, leaving the surviving member framed. The second caper is to recover the stolen information and expose the mole.
The MIT kids do this to their teacher in 21.

Literature

The Jeffrey Archer book Not A Penny More Not A Penny Less is about a stock market fraud and the subsequent attempts of the defrauded parties to steal back the exact amount they were scammed out of. At the end the originally worthless oil company stocks are suddenly valuable--after an oil strike nearby--and they have to find a way to run the whole theft in reverse to return the money.

Live-Action TV

The pilot of Leverage, "The Nigerian Job", has a team of thieves hired to steal a set of airplane plans from a rival aerospace corporation. They're told that the rival corporation stole the plans first. Then their employer doesn't pay them and tries to kill them, and they learn that he'd lied and they'd stolen the plans from the rightful owners. Counter-caper time.
Standard Operating Procedure in Hustle. If they're trying to surprise you, it might be a Triple Caper instead. Or even (GASP) a Single Caper. OK, I'm exaggerating... let's just say it happens a lot.

New Media

Jeremy Archer finds this out in the first novel of the Shadow of the Templar webseries, The Morning Star.

Video Games

Much of the pre-credits plot of Pokémon Mystery Dungeon: Explorers of Time/Darkness/Sky qualifies. (At least, if "keep Grovyle from stealing the Time Gears" counts as a caper.)
The plot of Ratchet and Clank Going Commando.
Garrett, the genius thief from the classic Thief, does this to Constantine after a rather painful discovery.
Mercenaries 2 - The first caper is the tutorial area. After your employer refuses to pay the bill, you spend the rest of the game hunting him and his dragons down.
Uncharted 2's second level sets this up, to some degree. Also in Eye of Indra.