How 'Parasite' delivered one of the best twists In cinema

• Bong Joon-Ho's screenplay for "Parasite" is virtually flawless.
• But what makes "Parasite" so shocking is the twist that happens all in a 10-minute sequence.
• Parasite doesn't follow a typical three-act structure, because it is actually two movies combined into one.
• Bong Joon-Ho uses imagery like windows and stairs to establish themes early in the movie that occur later in the film.
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Following is a transcript of the video.

Bong Joon-ho's "Parasite" is a virtually perfect film on every level. On the surface, its technical execution is so precise and immaculate that it's hard to notice the film's greatest achievement hiding underneath: the screenplay. For Bong, who has written every single film in his career, "Parasite" is essentially a culmination of everything he's learned over the years. But in its more than two hours of runtime, there is a single moment that truly exemplifies his genius, a sequence that transforms "Parasite" into cinematic perfection.

[doorbell rings]

Like all great stories, "Parasite" has a beginning, a middle, and an end, yet it never quite follows the usual three-act structure we're familiar with. Instead, the film plays a lot like two separate movies that are joined into one. The first film deals with the two families: the impoverished Kims, who plan to infiltrate the wealthy Parks by each posing as a tutor, a driver, and a housekeeper.

But it creates an odd moment in the story about 50 minutes in, after the Kims have removed all of the existing employees to essentially take over the house. Suddenly, there's no conflict left to carry the film, and the story comes to a literal stop. But it's the sequence that bridges the end of the first film to the unexpected second where Bong stages his attack. Let's take a look.

Bong begins the sequence by visually establishing the Kims' false sense of success, having dedicated an entire previous sequence to show the Kims reaping the rewards of their scheme. But he does it most effectively with a simple parallel image using a window, a motif of luxury that was introduced earlier in the film. The Kims, who had previously been subjected to the views of ordinary life outside their basement apartment, discover privacy as a form of luxury.

Yet, despite all of this, their success is only downplayed by their dialogue, which emphasizes just how far they are from it.

Bong keeps the dialogue engaging by faking out three moments of tension that gradually build over time. These moments are known as beats in a dialogue. Each beat organically interrupts and changes the flow and the topic of conversation. Until it seemingly explodes on the third beat.

[glass shatters]

[both laughing]

[doorbell rings]

It's no coincidence that this doorbell marks the exact midpoint of the screenplay, appearing on page 71 out of a 141-page script. It's a sound that signifies the end of the first film and what Bong refers to as "the real start of the film."

It's a brilliantly foreboding moment after a series of peaceful sequences. The audience is aware that something is about to go wrong, they just aren't sure what it is.

This is probably the best moment to talk about the films that inspired "Parasite." Bong has mentioned several, and the most obvious is Kim Ki-young's 1960 film "The Housemaid," which features a similar story about a poor maid infiltrating the rich. But thematically, its most interesting inspiration comes from Akira Kurosawa's 1963 film "High and Low," one of the first films that used height as a visual representation of class, with the rich towering above and the poor living underneath. "Parasite" expands upon this idea through another visual motif introduced earlier: stairs. On second viewing, it's incredible to see how vertical the film is right from its opening image. Whenever a character climbs a flight of stairs, it's a visual symbol of the rise in the social class, while the walk down suggests the opposite. Just like the window, it's this very sequence where Bong starts to take advantage of all the visual concepts he set up earlier, and it's the reason why we feel so uneasy in a moment like this.

The film that most heavily inspired "Parasite" is probably Alfred Hitchcock's "Psycho." The two films share a surprising number of similarities. Both mainly feature a house that almost becomes a character itself, the architecture guiding the film and sometimes hiding the truth in plain sight on another level. And, most importantly, the game-changing twist midway was also done most popularly by Hitchcock in "Psycho," who killed his main character exactly halfway through the film.

What makes the twist in "Parasite" so great is that it's as predictable as it is impossible to see coming. The basement in question is featured only twice in the film for less than a minute before its actual role is revealed. But it's a twist that doesn't feel out of question, as we've seen it happen already, just through the eyes of another family.

The truth finally reveals itself. And Bong expertly reveals the twist strictly from the Kims' perspective through a handheld camera. As the lighting, camera, tempo, and even the genre of the film changes, what awaits at the end of the tunnel is an entirely different film. All in 10 minutes of a sequence.

What makes "Parasite" so perfect is that it understands the rules and power of storytelling. Everything on screen has a specific purpose and a meaning that transforms the story as it unpacks. And it's ironic that, as brilliant as Bong's plan for the story is, the genius of "Parasite" lies in the 10-minute sequence where an entire plan is demolished on sight.