Obstacle Exposition

""The only person allowed inside has to pass through a series of security checks. First is voiceprint identification. Then, he has to put in a 6 digit code. That only gets him into the outer room. Next, he is positively identified by retinal scan. Finally, the security measures are only deactivated after insertion of a double electronic keycard... which we won't have. Once inside the vault, there are 3 security systems in operation whenever the technician is out of the room. First is sound sensitive; anything above a whisper will set it off. The second is temperature-sensitive. Even the body heat of an unauthorized person inside the vault can trigger the alarm if the temperature rises just a single degree. And that temperature is controlled by an air conditioning vent 30 feet above the vault floor. That vent is guarded by a laser net. The third one is on the floor, and it's pressure sensitive. Just the slightest increase in weight will set it off. And any of these systems, if set off, will trigger an automatic lockdown. Now believe me when I tell you, gentlemen, that all 3 systems are state of the art.""

- Mission: Impossible

A standard ingredient of the Impossible Mission plot: after having outlined the goal for the episode, Mr. Exposition will describe a list of all the insurmountable obstacles that stand in the way of that goal.

It could be an elaborate security system, along the lines of "The medallion is sealed in a box of three-foot tempered steel, which is monitored by heat sensors and motion detectors, in a warehouse that's locked with a security code and voice recognition and retinal scan, and is surrounded by nine hundred armed guards..." This is often illustrated by the camera focusing on each obstacle in turn.

If the exposition is worked from the outside-in, the obstacles are sometimes each explained as they are overcome. What also often happens is one character mentions all the Description Porn they can of the castle they are going to storm and a second character explains the exact details of how they can get around all the traps and not be seen.

It's not always as blatant as you might think it is, and the purpose is not necessarily for exposition, but it is a method of making the audience and the characters on the same wavelength. When the plot is moving at high speed and the characters act in a certain way the audience is not narratively left behind.

If they don't explain it in full that wouldn't be this trope and would likely fall under the Unspoken Plan Guarantee. If, during the planning stage, someone mentions a back-up plan in case a certain portion goes sour, you can also expect them to have to resort to that backup plan. See also Mission Briefing.

A subtrope of Description Porn. See also the "I Know What We Can Do!" Cut, where a plan and its obstacles are described to the audience while the characters are actually executing it.

Advertising

 * The old commercial for the game Mouse Trap. Turn the crank, snap the plank, etc...

Fan Fiction

 * In the Calvin at Camp episode "Legends of the Hidden Campus," an Affectionate Parody of Legends of the Hidden Temple, Eddy creates one of these that makes the original show look ridiculously easy by comparison. Of course, Eddy blatantly cheats.

Film
"Saul: I have a question: Say we get into the cage, and through the security doors there and down the elevator we can't move, and past the guards with the guns, and into the vault we can't open... Rusty: Without being seen by the cameras. Danny: Oh yeah, sorry, I forgot to mention that. Saul: Yeah well, say we do all that... uh... we're just supposed to walk out of there with a hundred and fifty million dollars in cash on us, without getting stopped? (long pause, everyone looks at Danny) Danny: Yeah. Saul: Oh. Okay."
 * In The Matrix Reloaded, the obstacles needed to overcome before Neo can open that final door are narrated in the background, during a montage of the teams accomplishing their tasks. It only switches to regular pace when Soren's team fails. The video game Enter the Matrix, however, details the adventures of Niobe and Ghost at the power plant that were not covered in the movie.
 * Subverted in National Treasure. Riley attempts to do this, but Ben's Plan is to move the Declaration elsewhere that lacks said security via a plan involving his knowledge of the people involved.
 * Practically codified by the first |Mission Impossible film.
 * Fun bit: The film Entrapment also has a sequence like this; during the montage in a possible Shout-Out to Mission: Impossible, the man who runs the Y 2 K bank system shutdown critical to the attempted $8 billion heist also ran the CIA room that was thieved in M:I.
 * Oceans 11:


 * Star Wars A New Hope has the briefing before the attack against the Death Star that clearly outlines their mission of hitting the exhaust port and everything that can possible stop them. This includes the need for tactical computers to make such a shot, and for good measure there was an unsuccessful attempt mid-way through the battle.
 * Saving Private Ryan completely set up the strategy and purpose of their Last Stand, including "The Alamo" and blowing up the bridge if the enemy troops get too close.
 * Shaun of the Dead had Shaun plot out their every move to Ed once they've realized they're in a Zombie Apocalypse as a monologue over hilarious footage of him carrying out each act, calmly and with panache. As Ed reminds him about something else Shaun amends his previous plan to accomodate it. From then on they, of course, have trouble each step along the way.

Literature
""How about if we kill everyone?" said Cohen. "A good idea, but impractical," said Mr. Saveloy. "And liable to cause comment. No, my current methodology is predicated on the fact that Hunghung is some considerable way from the river yet has almost a million inhabitants. And the local geography is quite wrong for artesian wells. And yet there is no visible aqueduct, you notice. Which rather leads me to doubt the saying that not even a mouse can get into the Forbidden City," said Mr. Saveloy, with just a trace of smugness. "I suspect a mouse could get into the Forbidden City if it could hold its breath.""
 * Pick a fairy tale, any fairy tale. The father who likes to watch prospective sons-in-law die, the little old man you weren't a jerk to, and even the victim of the curse will give you a long, detailed "to do" list. Just to shake things up, you will screw up at least one of the instructions in a What an Idiot! moment.
 * Pan's Labyrinth mainly follows this formula, but large parts are clearly obfuscated, which sets the audience on edge.
 * Tends to happen a lot in Artemis Fowl, mostly because the villains are fond of elaborate, high-tech security systems. (Considering that the protagonists manage to break into the impenetrable safe every time, the villains have good reasons to beef up their security.)
 * The book version of The Man with the Golden Gun is even older than the Mission: Impossible example, as it details the inner workings of how MI-6 (nee Universal Exports) deals with people claiming to be James Bond.
 * Interesting Times:

Live Action TV
"Olmec: You could start by..."
 * Subverted in Stargate SG-1. Jaffa Master Bra'tac details the massive defenses between the team and the ship's Applied Phlebotinum, which they will have to fight their way to... at the bottom of a large shaft that they are standing next to. O'Neill shrugs and drops several grenades down the shaft.
 * Firefly episode "Trash" plays out in much the same way as the The Matrix Reloaded example, except for things going awry at a different point.
 * "Ariel" also has one.
 * The last round of the old Nickelodeon game show Legends of the Hidden Temple was always a giant obstacle course, prefaced by a long-winded exposition of the many paths and obstacles within the temple.


 * The final round of Nick's |Double Dare has a laundry list of many different messy and non-messy items for it's obstacle course bonus round.
 * Leverage features an interesting version of this where Hardison explains how impossible stealing the painting is while a rival group of thieves does it during "The Two Crew Live Job".
 * J.D. Roth's Fun House is quite guilty of this.

Western Animation

 * In an episode of The Fairly OddParents where Timmy wishes to have no emotions, federal agents hijack him to give him an insanely dangerous mission, and are shocked when he calmly agrees to the mission after hearing the absurdly dangerous premises.
 * In the show Archer, Archer is heard describing the so-called security guarding the ISIS mainframe, while a montage of him bypassing each section in turn plays. Subverted in that he is actually just describing the security to Cheryl, in hopes that she, as a front desk secretary, has the ability to make it easier for him.