It is probably impossible for any hero’s journey to avoid thresholds and people/monsters/obstacles that serve as guardians of these milestones.
A threshold can be any dividing line between one point and another. Anything: a doorway, a fence, a river, a way off planet—any barrier is a threshold. The hero will go through several throughout his journey and each one is important because each means he has “made it” to the next phase of his journey.
Often the hero will have to bypass or defeat a person or thing that makes getting through the threshold rather difficult. These beings or obstacles are called “Threshold Guardians”—their purpose: to stop the hero in his tracks.
The most important threshold in any story is most likely the first one: the one that divides the hero’s ordinary world from the sacred world (see my post on “The Call”), but there will be many, and probably an obvious one before the climactic end scene.
While I will have several examples of thresholds and their guardians in my normal film list below, it would be silly not to mention the most plainly magnificent threshold guardian of all time: The Black Knight in Monty Python and the Holy Grail. The Black Knight guards a bridge over a creek no wider than a few feet, but simply stands there and repeats, “None shall pass,” so that King Arthur has to defeat him in combat (except, does he really? Why not just walk a few feet away and hop over the gully?). The Black Knight’s sole purpose is to be a threshold guardian. It is ridiculous and awesome. Please watch the scene even if you don’t have time for the entire film. I’m sure you can find it on Youtube.
• Major League: During spring training, the coaches are threshold guardians who will decide whether or not the individual players make it into the major leagues. After that, the coaches become true mentors while each team they face can be seen as a threshold guardian trying to prevent the Indians from winning and making it to the playoffs.
• Stand By Me: When the boys first step onto the tracks, they pause at the bridge—an obvious threshold separating their hometown from the unknown. Minutes later, they encounter the threshold guardian: Chopper—the dog in the junkyard. Of course, when they try crossing the big river, the approaching train becomes a threshold guardian that very nearly kills them.
• Harry Potter: Wow. Where to begin? Harry’s stepparents are threshold guardians, trying to prevent Harry from entering the sacred world of wizardry. Then there’s getting into Diagon Alley, the train station and platform 9 ¾, and a billion special thresholds within Hogwarts. Many of these have obstacles making it difficult for normal people to get through. Toward the end, Fluffy (a giant three headed puppy) guards an entrance just as Cerberus guards the land of the dead in Greek mythology. Really, there are probably a hundred thresholds in each book in the series.
• The Godfather: While there are many thresholds and guardians in this story, including Michaels’ own family members who do not want him to get involved in the family business because they want something better for him, some of the most obvious thresholds are the doorways in the restaurant scene with Michael kills Sollozzo (an act that irrevocably makes him part of the sacred world and leads to his crossing the ocean and hiding for several years). My favorite threshold, however, is in the final scene—the final shot, when Michael tells his wife, Kay, never to ask about his business and then, as she stands in the hallway, looking into Michael’s office, the door (threshold) slowly closes and she is left on the outside.
• Batman: In Batman Begins, Bruce Wayne has to get out of prison (an obvious threshold) only to climb a mountain (another) and then survive his training before returning to Gotham City (yet another). His journey began when he left Gotham (threshold) and went to China. You’ll be able to find many more throughout The Dark Knight Trilogy—though the 3rd film certainly has more than its share once Bruce is left in a seemingly inescapable pit (which he does escape) and returns from around the world to Gotham (never mind that he is actually penniless at that time and the entire city is sealed off—he’s Batman, so he can make it).
• Lord of the Rings: The thresholds and their guardians are obvious and ubiquitous in this story, so I’ll just mention one of the more subtle examples: when Frodo and Sam are leaving the Shire. The two Hobbits have been walking for a long while, when Sam suddenly stops where a line of wheat turns a different color. He tells Frodo that if he takes another step that “[He’ll] be farther from home than [he’s] ever been.” He pauses because, though it is just a line of wheat, it a huge step for him. Sam is crossing into the world of the unknown. I also really like that there is a scarecrow there—a silent guardian who gives Sam additional reason to pause and that serves as a warning of what is to come.
• Star Wars: As with Lord of the Rings and Harry Potter, I could make a long list of thresholds and guardians, but if we look at Episode IV (the original, original film), Luke’s Uncle Owen is a threshold guardian who doesn’t want Luke getting involved with the adventure plot. After Owen has been barbequed, Luke is free to do as he pleases, but still has to find a way off his home planet of Tatooine. Some Imperial Stormtroopers (who are repeatedly used as threshold guardians) question Luke and co., but Jedi Master Ben Kenobi is able to use a Jedi Mind Trick on the weak minded soldiers and get past them. Even when the heroes board the ship that will take them to the stars, they are attacked by Stormtroopers who wish to stop them.
• Skyfall (James Bond): Bond always faces a number of henchmen, each of whom can be seen as a threshold guardian who seeks to stop Bond from continuing on his quest/mission. In Skyfall, we also see Bond having to pass a number of tests to get back on the active duty list. In this case, his superiors are the threshold guardians who will decide whether or not he can continue.