WARNING: The following post contains plot spoilers from the movie Frozen.
We've all heard the debate about prologues. Use one and condemn yourself and your novel to certain doom in the publishing world. Or use one and be the greatest thing since Harry Potter.
Without getting into all the mechanics of the argument (is a prologue lazy writing? the chance to dump back story? something readers never actually read?) I'd rather analyze an effective prologue.
The Disney movie Frozen starts with an extended prologue.
Meet Anna and Elsa, princesses of Arendelle, perhaps four and six or seven years old, respectively. Anna wakes Elsa one morning for some pre-breakfast horseplay with Elsa's magical powers. Elsa can create ice and snow, perfect for making the ballroom a skating rink or the site of an enthusiastic snowball fight.
When Elsa accidentally injures Anna with her power, it takes a harried race to visit the rock trolls, the only ones who can cancel out the injury.
In the rest of the prologue, Elsa and Anna are kept apart while Elsa tries to learn to control her powers. Their parents die unexpectedly when the girls are teenagers, and the sisters continue to grow up estranged.
Why is this prologue effective when so many aren't?
Show Vs. Tell
If the movie had begun with Elsa's coronation day, which is the first moment in the chronological "now" of the plot, somebody somewhere would’ve had to go back and explain everything that happened up to the coronation.
That's called telling.
Telling is something to be used sparingly in fiction. Almost everyone will agree that you should show, not tell, if you can help it.
The Frozen prologue shows viewers all the necessary back story without the need for the main plot to stop so someone can say, "Well, you see, when Elsa was six or seven years old, and Anna was about four, there was an incident. . . ."
If your prologue is effective at showing the necessary back story and setup, and saves you from telling or throwing an information dump into your novel, use a prologue.
The second reason the Frozen prologue is effective is that it has its own neat story arc, albeit a small one, and shows (there's that keyword again) character development early, so we connect with our two protagonists from the start.
The child Elsa starts out as the more mature, more cautious, but equally fun-loving big sister. What carries her character through is her commitment to keeping Anna safe, even when that means avoiding Anna and learning to keep her powers hidden. The foreshadowing is particularly effective as Elsa's powers, and her fear of them, increases until her choices are defined by fear.
The child Anna is carefree and innocent, delighted with every occasion for merriment. She appears unchanged after the accident, but her young heart fills with confusion as at every turn Elsa rejects her company. Anna grows up a tomboy and becomes self-sufficient, used to filling her time with her own hobbies. Her later choices are defined by her assumption that her sister hates her.
Your prologue is an opportunity not only to set the stage for your work-in-progress but also to establish sympathetic characters from the very beginning.
Remember: Reader engagement is key above all else, even when considering the pros and cons of a prologue.
Does your work-in-progress currently have a prologue, or even a first chapter that might actually serve as a prologue because it's out of chronological order with the rest of the story? What do you want to accomplish with your prologue? How will you avoid the stereotypical problems that might arise?