Two Roads Before You

"You've got two roads before you: One is the path of righteousness, where you carefully walk the road to the light--the direct route. That's your merry co-op play. The other is the path of heresy, searching for power along the path to darkness--the indirect route. Single player. It fits a shut i--lone wolf like yourself."

—Jack Rakan, Mahou Sensei Negima

The Hero is confronted with a choice between two mutually exclusive paths. Sometimes it's the choice between good and evil, law or chaos, or even just choosing between fire magic and ice magic. The point is, only one path can be taken, and there's no way back.

The point of this trope isn't the choice; its the act of presentation. As long as someone is presenting the choice as if the options are mutually exclusive and important to the character's life from then on, it doesn't matter what the choices are or who is presenting them.

Shows up in video games quite often, even in games without a Karma Meter.

See also Sadistic Choice and Take a Third Option. Has some symbolic relation to At the Crossroads. Super-Trope of Red Pill, Blue Pill.

Note that this trope can apply to events with more than two choices, so long as they are all still mutually exclusive.

Not to be confused with At the Crossroads which is a trope about a more physical crossroads.

Examples of Two Roads Before You include:

Anime and Manga

The Trope Namer is Mahou Sensei Negima, with Rakan explaining the difference between the main character's father's path and his master's path. Negi chooses the indirect route and begins the hard journey of mastering Magica Erebia, which transforms him into a kind of demon.
In Pokémon, Dawn had to choose between Kenny, her childhood friend, and Ash, with whom she had been traveling for a long time. Guess whom she chose?

Film

Shows up in Star Wars pretty often.

Yoda: If you leave now, help them you could; but you would destroy all for which they have fought, and suffered.

Morpheus offering Neo the red pill or blue pill in The Matrix.
- Also in The Matrix, after Neo is captured by the Agents he ends up in an interrogation room.

Agent Smith: It seems that you've been living two lives. In one life you're Thomas A. Anderson, program writer for a respectable software company. You have a Social Security number, you pay your taxes, and you help your landlady carry out her garbage. The other life is lived in computers where you go by the hacker alias "Neo", and are guilty of virtually every computer crime we have a law for. One of these lives has a future, and one of them does not.

- The Matrix Reloaded also ends with the Architect offering Neo a choice between two doors —one accomplishes his mission (sort of), the other saves Trinity's life. Neo chooses Trinity.
In The Dark Knight, The Joker offers Batman a choice between saving Harvey and saving the girl; likewise, he offers both a passenger-ship and a ship full of prisoners the choice of blowing up the other ship in order to save themselves. Also an example of the Sadistic Choice.
Aleu gets this question posed to her by her Spirit Guide, Muru. She can continue on and find out who she really is, or return home to her family and old life. This one gets bonus points for being posed in song.
In Thank You for Smoking the Original Marlboro Man has cancer and is a about to become a spokesperson for the anti-tobacco lobby. Nick presents him with a Briefcase Full of Money. The guy can take the money and provide for his family or he can decline it and speak out against his former employers. Nick makes it quite clear that the guy cannot do both and has to choose.

Literature

In Cry of the Icemark, the warlock has a choice between being good and being evil, and there is a very specific point in the text where he chooses: Simple, easy and powerful, or good? The choice was obvious. And then Thirrin spoke.
The Robert Frost poem The Road Not Taken.
This is the famous Choice of Hercules (or Herakles, if you want to be all Greek about it): The allegorical figures of Vice and Virtue appeared to him to offer him a choice between a life of pleasures without achievement, and constant striving with great accomplishments. The story, from Prodikos, is told by Xenophon in his Apomnemoneumata.
The hero of Le Roman de la Rose had to choose between The Rose and Reason.

Live Action TV

On Star Trek: Voyager, the Doctor is presented a choice between saving a friend and saving someone he didn't know well, and both had identical chances of survival. The guilt from choosing his friend drives the Doctor insane as it creates a conflict between his base programming and what he'd become.
Monty Hall's "The box or the curtain?" on Let's Make a Deal
iCarly: Spencer uses this analogy to help Carly decide between staying at Ridgeway or switching to the private school Briarwood in iMay Switch Schools:

Spencer: Listen, I'm your older brother. So I will help you through this difficult decision. Just... just close your eyes.
Carly: Okay. (She closes her eyes).
Spencer: Okay. There's two roads in front of you. Road A, and... the-the... one on the left. (Pauses, then runs out of the room).
Carly: (Opens her eyes, then laughs) Thank you!

Myth and Legend

In the Greek myth "The Judgment of Paris", he—had to choose among Wisdom, Power and Love (as personified by Minerva, Juno and Venus). It wasn't entirely a fair choice, though—all three goddesses used bribes. He chooses Love, and is thus given the love of the most beautiful woman alive - Helen, who just happens to be married already. This leads directly to the Trojan War
- Also from Greek myth, Heracles having to choose between an easy, comfortable life (pleasure) or a harsh, glorious one (virtue), he chose the latter.

Theatre

Pheidippides had to choose between the two arguments in The Clouds.

Video Games

The professor offering the player a choice among three starters at the beginning of every Pokémon game. There are also the fossils you can choose between in most versions, usually with a "fossil maniac" ready to take the one you don't grab.
Kingdom Hearts has the choice among the sword, shield and wand, presented by... a caption thing stating in unequivocal terms that the choice will shape the rest of the adventure.
- In Chain of Memories, at the end of Riku's story, DiZ tells him to choose the road he'll take. The road to light, or the road to darkness. Riku chooses the middle road. "The road to dawn."
The later Ultima games began with a series of two-choice presentations, between which of two Virtues conflict in hypothetical situations. In the end, the destination is the same, as the Avatar comes to embody all the Virtues. You do get better or worse stats depending on what you pick.

Western Animation

In Avatar: The Last Airbender, at the end of season 2, Iroh tells Zuko he needs to choose whether to side with either the Avatar or Azula. The episode is even called "The Crossroads of Destiny." He chooses Azula, but it turns out he can change his mind later with minimal negative consequence.
Played for laughs in the Adventure Time episode "Another Way," when Finn meets at a crossroads where he must chose between going down a path that will make his hair fall out or a path that will make him smelly forever. He ops for a third option: going straight through the middle of the two paths, which happens to be covered in thorny bushes.