Alright, I'll just lay out where this whole thing starts. We're in Arendelle, shortly after the end of the events of Frozen II. The wedding is about to begin, and Kristoff and Olaf are waiting anxiously at the altar for Anna. Elsa is at her designated spot nearby.
KRISTOFF
(Whispering to Olaf)
Why is she late? It's not like her to be late.
OLAF
(Whispering as well)
I know. She probably got a case of the butterflies and has decided to give up on you and your marriage and life in general.
ELSA
(Harshly but quietly)
Not. Helpful!
KRISTOFF
(Whispering)
Let the snowman talk. It's a free country.
ELSA
(Whispering, mildly sarcastic)
Tell me, Kristoff, is there anything in the Arendelle constitution or the Treaty of Northern Nations about rights for snowmen?
OLAF
(Whispering)
There is.
ELSA
(Whispering, confused)
No, there's- wait, what?
OLAF
(Whispering)
No one looks after me, so I pretty much do what I want. It's legal now. By the way, if a mob of angry Norsemen comes after you for about ten million in gold coins, just remember that it was an accident.
KRISTOFF
(Whispering)
An accident? What was an accident?
OLAF
(Whispering)
Shall we change the subject?
An organ starts playing, the doors swing open, and there's Anna. I'll skip the vows and stuff cuz that's all cheesy and I want to write A) the action scenes and B) the heart-wrenching scenes. So, I'll sum up below.
Anna walks down the aisle, Kristoff sheds a tear, the word "Trollfully" is used by Pabbie, the pastor, for Anna's vows, Kristoff has some heartfelt custom vows, and Olaf fakes retching at the kiss. Also, Sven was present for all of this, but I haven't written him in yet. Sven is there.
Alright now, let's fast forward a bit. Four months, to be exact. An important letter arrives from another nation. Anna takes the letter from the deliverer (?), who took it up to her and Kristoff, who are playing chess in the library.
LETTER DELIVERY GUY
(To Anna)
Your majesty, you got an impor-
ANNA
Shh! I'm about to win.
KRISTOFF
Uh, no. I'm about to win.
ANNA
Tell that to my rook.
Anna moves a piece to a square and takes the letter as Kristoff stares at the board, astonished about his loss.
KRISTOFF
I didn't see that coming.
ANNA
No. No, you didn't.
KRISTOFF
What's that letter about? The one that distracted me from my game?
ANNA
Okay, A: it was my move and I won, so you weren't distracted. And B: this letter is from Kalnor.
KRISTOFF
Kalnor? The small republic south of Corona?
ANNA
Well, what other Kalnor could it be?
KRISTOFF
What do they want?
ANNA
(Looking over the letter)
It's an invitation. For me, as queen, and you as best boy-
KRISTOFF
*puppy eyes*
ANNA
(Joking around)
I mean prince consort- to go to Kalnor to negotiate a new peace settlement with the Northern Nations. There's a new king of Kalnor, a new queen here, obviously, and…
Anna doesn't speak for a moment.
KRISTOFF
...And?
ANNA
(Trying to hide fear)
A new king of the Southern Isles.
Here, I could put a song in that I've been thinking of, but I've only got a basic tune and a few lines of lyrics. Maybe I'll edit it in someday or it might not ever get written. Whatever. Anyway, back to our scheduled reading.
Immediately, Kristoff puts his arms around Anna and holds her tight.
KRISTOFF
Forget Hans. Forget everything that ever happened with him.
ANNA
It's hard. You haven't seen it, but because of him, I have a hard time trusting people not already on my side. You don't know.
KRISTOFF
Hey. I got you. Nothing's going to hurt you.
ANNA
(Pushing back a little from the embrace to end it)
I'll be fine. I- I'm fine.
KRISTOFF
Do you really have a hard time trusting people who you don't know?
ANNA
(Sighs)
That's for me to work on.
KRISTOFF
When I married you four months ago, I agreed to make your life mine. We're in this together.
ANNA
I guess so. For life.
Here we'd expect to see a kiss or something, but what I'll do is take us straight ahead another while to Kalnor.
A quick note here: Anna saying she has a hard time trusting anyone is quite important, and will definitely factor into the plot's main structure.