This is, without a doubt, the most important scene in your story. This scene needs to take your protagonist out of their status quo and commit them to the rest of the story arc. Without this scene, you have no story.
A brief word on semantics. Some call this the inciting incident. Some call it the first turn. For avoidance of doubt, it’s the scene at the end of Act One that propels your hero on their journey. I call it the First Plot Point. Call it what you will, it has the same purpose.
So what are the elements of a good First Plot Point?
You need an Act One first. And a good Act One needs to set up your story with sufficient information to a) hook your reader and b) make your reader care enough about your hero to be impacted by whatever happens in Act One.
And no more.
If your First Plot Point is too early in your story, you’ll have very likely not set up your story enough. And if it’s too late, the reader won’t wait for it.
A turn of events.
The First Plot Point needs to appear, even if metaphorically, as if the hero is crossing a threshold, either willingly or not, committing themselves to the adventure. Subtle or as obvious as the nose on your face, it has to happen. And it has to be irrevocable. No turning back.
In so many cases this threshold crossing is done in error. A classic example is Homeward Bound, that great kid’s movie following two dogs and a cat as they cross the country in search of their owners. The First Plot Point in that movie is the decision Shadow (the older and I’d argue, dumber, dog) feels that things aren’t quite right:
Shadow: Something doesn’t smell right. They’ve been gone way too long. Much longer than they should have been. Something’s really wrong.
Chance: Wake up and smell the kibble. They dumped us!
Shadow: No! It isn’t true!
And this triggers their grossly unnecessary walk on the wild side.
A more recent example? Ant-Man.
Scott Lang (Paul Rudd) has slipped back into a life of crime and, thinking he’s on to a big thing, steals the Ant-Man costume, not realising that Hank Pym has set him up. The First Plot Point is Scott putting on the outfit, then shrinking himself to water drop size in the tub.
Hank Pym: The world sure seems different from down here, doesn’t it, Scott?
Scott Lang: Who said that?
Or how about The Avengers: Age of Ultron? The First Plot point in this movie is like a punch in the face from Thor.
The Avengers are standing around, assembled, as it were, trying to lift Thor’s Hammer (And that’s not a euphemism) when guess who shows up. In a really bad mood (not that fond of humans) but Ultron himself, in a fantastic piece of dialogue:
Ultron: [Loud ringing noise fades into Ultron’s voice] … worthy… No… How could you be worthy? Your all killers.
Steve Rogers: Stark.
Tony Stark: JARVIS.
Ultron: Sorry I was asleep… Or… I was a dream…
Tony Stark: [Tapping his phone] Reboot, we got a buggy suit.
Ultron: …There was a terrible noise… And I was tangled in… in… strings… I had to kill the other guy… He was a good guy.
Steve Rogers: You killed someone?
Ultron: Wouldn’t have been my first call. But, down in the real world we’re faced with ugly choices.
Thor: Who sent you?
Ultron: [Replaying Tony’s voice] “I see a suit of armour around the world”.
Bruce Banner: Ultron!
Ultron: In the flesh. Or, no, not yet. Not this… chrysalis… But I’m ready. I’m on a mission.
Natasha Romanoff: What mission?
Ultron: Peace in our time.
Thus committing the Avengers to battle.
Oh, yeah. This FPP was the result of a mistake, also. One that had Thor attempt to tear Tony Stark’s head off.
Bottom line? Whether it’s subtle or a smack in the face, your First Plot Point needs to commit your hero (or heroes) to the story.