Year 2940 Third Age, Middle Earth.
"My Lord Arathorn! My Lord, the orcs attack us from the north. There must be at least one hundred of them. We are surrounded. I don't know how much longer we can hold out!"
"Baeron, where are my children?!"
"They were in the gardens the last time I saw them, my Lord, but that side of town has already been taken!"
A terrible fear immediately took hold of the King: he couldn't lose them, his children, his heirs, the last of his line. He knew they wouldn't win that battle. He knew by reputation Gundabad orcs, They were ruthless beasts, trained to fight, and they were superior in numbers: it would have been impossible to defeat them. But his children had to live, they had to escape at all costs.
The King heard a voice calling him in the midst of the noise of the battle.
"I'm here, father!"
That voice again. Arathorn knew well who it belonged to. It was his son, Aragorn, who was calling him. He began to run towards the child, hacking and slashing as many beasts as possible, in a desperate attempt to keep him safe. A 9-year-old boy, not used to the horrors of battle, was looking for him from a high ground in the middle of the destroyed city.
He came close to him and brought him into a breach in the walls now fallen, so that he could talk to him.
"Aragorn, you must flee..."
"No, but nothing! Listen to me, kid. Take your sister and head south, follow the Misty Mountains to Rivendell. King Elrond will take care of you."
"Father I will not leave you! Not now! I can fight, you taught me!"
"No Aragorn, there's no hope for you if you stay, you cannot fight, not today. There will come a day when you will show your strength and your courage, changing the fate of history, but it's not today."
The King told his son, gently putting a hand on his shoulder.
"Here, I want you to take this. It's the Ring of Barahir, all the great Kings of Gondor have worn it, and your turn will come sooner than you think, son. Go now, find Arya and go South!"
The boy tried to argue again, holding his father's hand tight, which was still resting on his shoulder. But it was useless, Arathorn would not listen to reasons, he had to send his children away and was running out of time.
"Go South! Take the eggs with you, burn them! They must not have them! Goodbye Aragorn."
That being said, Aragorn ran as fast as he could, heading to the palace without ever stopping.
The battle raged all around the boy, but he kept going, swift as the wind, dodging orcs' blows and trying to pass unnoticed. Then he saw her, his twin sister, Arya, surrounded by four hideous creatures ready to tear her to pieces. He mustered up all his courage, took the sword in his hands and began to face them. He was not afraid, not at that moment,at that moment he felt only an extreme anger. Anger, because he had to leave his father, his mother, his friends, his home. Anger, because the flames were blazing in his city, which was now falling apart, destroyed. Anger, because his childhood was being torn away from him and there was nothing he could do about it. All due to an Orc that neither he, nor his sister, could ever forget: Azog the Defiler. With these thoughts in mind, Aragorn slew his enemies, took Arya by the hand and together they ran towards the palace. As quickly as possible they collected some supplies, recovered some weapons and three dragon eggs, jealously kept in a casket in their father's quarters. Then they headed to the stables, where they mounted the two fastest horses in the North, Elendil and Andoras. They were young, yes, but they were already skilled knights.
Leaving the city wasn't so hard, not practically at least. Morally, they never left it.
After a long journey, mostly occupied by sadness, melancholy and fear for their fate, the two children arrived in the Valley of Imladris, the last welcoming house east of the sea. King Elrond was waiting for them, he knew of their arrival: he had foreseen it. Aragorn and Arya, exhausted by the journey, received a warm welcome in Rivendell: they finally had a bed to sleep on, a hearty meal and the assurance that nothing would have happen to them, as long as they remained there. Elrond was a good and wise king, he took care of the children, keeping the promise he had made to Gilraen long before.
Arya and Aragorn grew up quickly. Their childhood had been stolen by orcs, but in Rivendell they were still able to find the lightheartedness and the happiness that every child should know. They soon learned how to fight and became excellent warriors, capable to handle both bow and sword. They were taught everything there was to know about Middle Earth: its history, its geography, its inhabitants, each people with its language and culture. They studied medicine and herbology, and some of the simplest magic spells. Moreover, soon came to them the awareness of their name and of what it meant to be Isildur's heirs, although King Elrond advised them to keep their identity hidden, for safety.
At the age of 20 Aragorn decided to leave for the North, with the intention of reaching the Dúnadain, and finding information about their father. Having to part from her brother was really painful for Arya, but she knew he had to do it, it was his duty, his people needed him, they needed a guide.
The night before leaving, Aragorn gave Arya the Ring of Barahir, which had always belonged to the line of Isildur. Arya was hesitant to accept it: it wasn't up to her to have that heirloom, Aragorn had always kept it, since his father had entrusted it to him before saying goodbye many years before, but at least she would have had something more than the only memories to hold on to on nights when she was lonely. So she eventually took it and put a silver chain through it, than she tied it behind her neck and never took it off again.
After Aragorn's departure, however, there was still an issue to be addressed, an issue that would have changed the girl's life forever. The dragon eggs.
* Gilraen: mother of Aragorn and Arya