Jack sees Elsa for the first time as a kid playing with Anna and he's sort of watched her on and off since. He's heartbroken when she's hidden away but one of the few benefits of so few people believing in him is that he can still get into the castle without any trouble. He's an unheard voice of support trying to tell her that what she does is beautiful. He stops in every couple of years and is always saddened by what he sees. He thinks that Elsa has amazing gifts and he can't believe that she's hiding herself away instead of using them. He can't believe that this is the best idea her parents could come up with and that Elsa spends all of her time isolated and sad. He knows what that feels like and it's terrible. Elsa is just like him, you'd think that at least she would be able to see him right? He's a Guardian now, shouldn't more people talk about him? Especially to someone with ice powers?
Unfortunately, between being cut off from the world and resistant to anything regarding her magic she's certainly never heard of Jack Frost. Jack tries not to be sad about it. So he just hovers and watches over her. When he's there he finds himself hoping that she can somehow sense his support.
He feels winter come out of nowhere in Arendelle when it's supposed to be summer and the next thing he knows he's grabbing a gust of wind and he's there to see what is happening. He watches the snow spread and he finds Elsa running away up to the mountain. He watches her finally pull out of her shell and WOW he's never thought to use his powers the way she does when she's suddenly building a bridge and a whole castle.
He doesn't even think he can do what she is doing. Most of what he does is influential. There just aren't enough people believing in him to do more. He can bring on a snow storm, move the wind, make frost wander across things, but he doesn't have this much power to shape things. Wow, she's actually created two living beings. He finds himself wondering if he could do this with more power. After all, the Bunny has eggs that do his bidding right? And clearly you can make ridiculous talking snowmen and scary monster guards out of snow.
He's getting distracted. Something is happening here and it's terrifying because Elsa is losing her kingdom and her sister. Really now, he pulls at his hair frustrated, he wandered off for a day and somehow Elsa's been captured and locked up and Anna is missing. He could have sworn he saw Anna traveling with a friend, how does this family get into trouble so quickly?
He can't help. Nobody can see him and Elsa is so upset that she's making a storm so thick that even he is having trouble seeing anything in it. He's on top of a ship in the frozen water hoping to see something when the storm breaks. When he watches Anna freeze solid and terror grips he heart reminding him of his sister. He knows that feeling, he doesn't want to see Elsa go through that. Does he even know how to unfreeze things? He's pretty sure he has no advice to give in this situation even if Elsa could hear him.
Anna is thawing… everything is thawing. Jack finds himself clinging to the boat suddenly as the water thaws and it rocks to one side before righting itself in the water. It looks like summer is back in Arendelle.
He can't believe he just witnessed such a stressful adventure in a place where nobody seems to believe in him. He hasn't even seen a kid glance at him and that's usually what he gets. He has to get back to the other side of the world, back to winter and fun and maybe he'll go indulge himself for a little while somewhere he knows there are kids that can see him.
He's never been able to resist checking up on Elsa. Besides he's the Guardian of Fun and it's winter in Arendelle, he's obligated to make sure that Elsa is actually doing something fun with her powers rather than sitting inside and being a serious Queen. He just can't allow that. She barely got a childhood hiding out in her room. Her kingdom seemed accepting when he last left her, it's time for her to enjoy herself. Hopefully Anna got her to have some fun, Anna was always good at saying the things that Jack wished he could make heard.
When Jack gets there Elsa is in a frozen courtyard, it's got a layer of ice where people are skating and pretty frozen fountains and Elsa seems to be working on a smaller version of her impressive mountain castle for everyone to be able to play in. Jack perches himself on a fountain to watch and finds himself wondering where Anna is… AHA he knew she'd made a friend. There's a tall blond man talking to her and they seem to be arguing in a friendly way about something.
He's soon distracted by the Castle that Elsa is building instead. There are kids running around Elsa as she brings this castle to life in front of them. A young girl asks for a tower and Elsa makes it appear, another girls suggests a slide to get down from the tower and laughs as Elsa makes the ice change shape. They're laughing and screaming and it's so clear that these children absolutely adore Elsa. They're soon laughing and climbing and sliding all over the ice. Jack finds himself standing there watching, he's a little envious and a lot sad. Sure, more people believe in him, there's usually at least one kid in a town that sees him and goes wide-eyed, but he's not loved like this.
He'll probably never be loved like this. He's no Santa Claus.
Kristoff really has no idea how he ended up best friends with a princess. A ridiculous and occasionally very naïve princess. Less than a year ago he just wouldn't have believed that he'd be spending part of his winter in a castle rather than bundled up with Sven out in the woods hauling ice. Not that he's not still hauling ice, but he goes out for a week or two and then comes to the castle for a few days. Anna wouldn't let him stay away for this winter celebration and he has to admit that he has no regrets. He kind of loves ice. He loves watching Queen Elsa work now that she's not terrifying and slightly unstable.
Princess Anna is distracted by a young boy who seems to be playing rough with Olaf. He has one of the snowman's arms in his hand and Olaf is laughing but Anna seems a bit anxious over it. She's gone to join in and make sure her friend is ok.
That's when Kristoff notices the young man watching Queen Elsa. It's a really strange site to see because the man is standing barefoot on the ice and really not wearing enough layers for the temperature that tends to follow the Queen around as she works. He's also leaning on a staff as he stands watching Elsa and has hair that Kristoff would think of as blonde except it's almost white like the snow at their feet. The man's eyes go wide and he grins and Kristoff curiously turns to see what he's looking at and finds Elsa working on making a frozen garden with very realistic looking flowers.
He turns back to look at the young man but he's gone. Or rather, he's moved and he's suddenly much closer to Elsa and her flowers.
Anna is back at his side as he gasps, the man is right in the way of Elsa's powers and Elsa doesn't seem to have noticed him at all. He's going to end up hurt and Kristoff knows Elsa still gets extremely upset when she slips up and he's about to move forward but he's too late.
"Kristoff? Kristoff! What is it?" Anna is tugging at his sleeve and he glances down at her, not sure how neither she nor Elsa noticed the man in the icy flower bed.
He gestures towards Elsa and gets a confused look back from Anna, "Didn't you see-?" but he's looking up and the man is fine. He's laughing and then he touches one of the flowers and Kristoff watches new patterns emerge all across the petals.
Anna is trying to follow his gaze and looking worried. "Flowers should not scare you like that. See what?"
There's a young man with ice powers playing in Queen Elsa's garden and it looks like nobody can see him. That's when he remembers a story Bulda once told him when he was still a child. He'd been talking about ice and how sometimes you could see pretty patterns where everything was frosted over and suddenly Bulda was teasing him about being in love with Jack Frost. She told him of a boy with ice powers who was around in winter, who drew on the ice and kept things frozen and watched out for children in the snow even as he made sure that they had fun. Kristoff remembers blushing and telling Bulda that he couldn't very well be in love with someone he hadn't met and he couldn't marry a spirit. She had just laughed and said, "What makes you think he's a spirit. Of course he's real, don't doubt that cutie." Kristoff is suddenly sure that that's who he's looking at. He's even more sure when the boy flies up in the air a bit and lands carefully perched on one of the frozen fountains.
Anna is starting to look concerned, very concerned. She's trying to follow where he's watching but she obviously can't see anything, "Kristoff, see what?"
Kristoff blinks and glances at her, probably looking a little wide-eyed, and just replies with "Jack Frost"
Anna looks confused and she's asking him questions but he's not paying attention because the young man, Jack, froze for a minute when he heard Kristoff say his name, realized he was being watched and suddenly he's in front of Kristoff barely a foot away and with an irresistible grin on his face, "You can see me?"