Disclaimer: If I owned Percy Jackson, this would have made it into the Demigod Diaries or something.

The first time anyone actually notices her, it is a boy. He is Italian, with dark hair and dark eyes. He is not taking the tour, he is just wandering around, but he is definitely new. She has never seen him before. She wonders briefly if anyone bothered to give him the tour.
His eyes land on her and before she knows it, she has company by the hearth.
"Hi." He extends a hand, and she shakes it, glad for a friendly figure after centuries. "I'm Nico di Angelo."
She considers hiding her true identity, but why? After all, he is the first one to speak to her in years.
"I am Hestia."
His eyes widen. She was expecting this.
"Like, the goddess Hestia?"
She smiles. "Exactly. I am the goddess of home and hearth, and, trust me on this, Nico, this camp is a wonderful home."
He doesn't seem convinced, but he sits down next to her all the same. "Aren't you supposed to tend the hearth on Olympus?" This boy is filled with questions.
"It is lonely up there. The other Olympians are rarely there, so I only go during meetings, when they are all there. Does that make sense?"
He tilts his head. "Kinda."
They sit in content silence for a few minutes until he says, "I've got your card. You aren't technically an Olympian, apparently, and your offense isn't that great, but your defense is a lot better- +10 if the enemy is invading your home, cause you're the goddess of home and everything, and your healing surges are really good, although they're not as good as Apollo's, but he. . ." The boy, Nico, trails off, looking embarrassed, but Hestia is thoroughly interested.
"What do you mean, you have my card?"
"Uh, it's Mythomagic. A mythology game, sort of. I'm kind of a collector. I collect. . . cards. And figurines and stuff."
Now she is curious. "And. . . I have good defense? And healing surges?"
He nods, his eyes lit up. "Yeah, you're kind of the last defense if Olympus is attacked, and since it's your home you have the +10 defense and everything."
She cannot help it. She begins to laugh. He flushes and ducks his head, but she controls herself.
"My apologies. I am not laughing at you. I am laughing at the idea that mortals are making a game out of us."
Nico smiles, although he is still blushing. "Are you offended?"
She considers this for a long time. "No," she finally decides. "Merely amused."
He shrugs, still smiling and says, "Uh, if you don't mind me asking. . ."
"I probably won't," she reassures him.
"What was it like in Kronos' stomach?"
The question catches her off guard, but she begins telling him all about how they would kick and try to make the Titan's stomach upset, and how she was the peacemaker for fights, mainly between Hades and Demeter, and soon they are both laughing, and neither can control it, and neither wants to.
Hestia decides right then and there that she likes it when people stop by.

However, no one else does, but Nico di Angelo returns one day, after a fierce capture-the-flag battle that, Hestia gathers from chitchat between two passing campers, ended with a bang- or, perhaps, a lot of green smoke and a prophecy.
He does not say much, and he does not look her in the eye, preferring to gaze at the hearth.
"My sister is going on the big quest."
"I did not know you had a sister," she replies mildly.
He shrugs. "She was all I had for years at our military school. Then we find out you guys are real, and she joins the Hunters of Artemis. And now she's going on a quest."
"Ah." There is not much else she can say. He clearly does not want sympathy.
"I. . . just don't know."
He is worried. He is so clearly worried for his sister.
And for once, there is nothing she can do.

He is back, very soon, the very next morning, actually.
"They've left," he says, and what can she say to that? She saw the van leave. And she could picture a female version of Nico riding in it.
"Percy's going too," he adds, and this was something she did not know. She raises an eyebrow.
"I. . . confronted him. Last night. He has an invisibility cap. He's following along. Invisible. And he's gonna protect Bianca."
Bianca. She assumes that is the name of his sister.
"She's going to be okay," he says suddenly, looking up at her. "Percy Jackson is protecting her. If Percy Jackson can't protect her. . ."
The words nobody can hang unsaid in the air around them.

The next time he visits her he does not look well. He is paler, much paler, and shadows hang beneath his eyes.
She wonders if he has slept at all.
"Bianca's dead," he says, as way of greeting.
Her heartbeat quickens. How does he know that? The questers are not back yet.
"How. . . how do you know?" she asks hoarsely.
"I- I feel it. It's just like a feeling. In my bones. I think she's dead."
He looks so bleak, so sad she cannot help but comfort him. "Do you know that for certain?"
He shakes his head slowly, but does not say a word.
"Perhaps your feeling is wrong. Perhaps she is alive."
"Maybe," he says, but he doesn't sound convinced.

The next time he comes back he looks even worse, and he has a bag slung over his shoulder.
"I'm leaving. I came to say goodbye."
She knew this would happen eventually. She knew as she watched him grow more and more distant with the other campers. Truly, she knew the moment he came to her with his belief that his sister had died, yet she refused to believe it.
She knows he has just found out that his belief is true.
"Where are you going?" she manages finally.
"Somewhere. Anywhere." He watches a satyr chase a nymph. "Away from here."
She cannot even picture such a young boy, no older than ten, living on his own, but Nico always was independent- much more so than most ten-year-olds. Than most campers, really.
They are silent for a few minutes. Finally he says, quietly, hoarsely, "I shouldn't have gotten my hopes up."
Her heart rips in two.
"Shouldn't have gotten mad at Percy either. Just wanted to be alone."
He did not want to be with anyone else, yet he goes to her. She is touched.
He is quiet for several more minutes.
"Goodbye, Hestia."
Two little words. Two little words, she discovers, are enough to make a goddess cry quietly, especially when the words are accompanied by a young Italian boy, so different than the boy he once was, standing up and walking away.
But then again, she always was weaker than other goddesses.
Quietly, almost to herself, she whispers, "Goodbye, Nico."

When she next sees him, it is a year and a half later, and he is with a friend.
She remembers the other boy. Percy Jackson- son of Poseidon if she recalls correctly.
They are tired, and Nico looks awful. She has to remind herself it has only been a year and a half; he looks like he has aged much more than that.
Her heart pangs with sympathy, but she cannot help but smile. She knew she would see him again. She just knew it.
They sit by the hearth. She supplies a feast.
She watches Nico eat, and she is torn between amusement and sympathy. How long has it been since the boy has had a decent meal?
She smiles softly, and whispers to herself, "Welcome home, Nico."

But he cannot stay for long. He has a world to save.

She sees him again, however, soon. It is him and his pithos, with Hope in it and Percy Jackson is there too. "I am the last Olympian," she tells them, and smiles at Nico. Did he get the joke? She thinks he did, but he is not smiling.

He never seems to smile anymore

He saves Olympus. She knew he would. However, he is not acknowledged as a hero, and is given no reward. She half expected this, but cannot help but be angry. Do they not see that Nico di Angelo deserves a gift as well? Apparently they don't. He doesn't get so much as a royal dust bunny.

There is an Olympian sized party. Nico skulks in the corner.
She goes up to him and asks him to dance.
His whole face lights up, and soon they're whirling around the room, laughing and dancing and Olympus is saved and everything is all right.
Finally he says, "So. . . uh, Olympus is safe."
She smiles. "Yes. And it's all thanks to you and your friends."
"Who? The skeletons?"
"No, silly. Your friends the demigods, remember them?"
He laughs. "Just joking around. But you know who really saved Olympus?"
She looks into his eyes- so dark and serious, although with a hidden pocket of mirth she can just barely see.
He grins. "You, and your +10 bonus attack if the enemy is invading your home."
She laughs, and as they twirl around the room, she thinks that hope may be best by the hearth, but neither of them need a hearth. Everything is perfect.

Author's Note-

I'm sorry if you didn't like the cheesy ending. And for those of you who are staring at your computer or whatever in shock, this isn't really meant to be Nico/Hestia. It just sort of came out.