Chapter One: Legacy

A/N: So, my first foray into the 100 fandom. I know that a lot of people write about Bellamy paired with an Ark OC or a Grounder OC. I'm aware that this might not be very popular considering it is (to my knowledge, at least) the first Mount Weather OC paired with him.

This chapter is mainly setting the scene, so there's no Bellamy yet, but I hope you enjoy it anyway. Please let me know what you think :)

She dreamed of what lay outside the cold stone walls of the mountain. It wasn't a fleeting dream. It didn't just pass by in a moment. It was something she had yearned for with her entire being for years. But every year that passed, every birthday made her all the more painfully aware of the fact that she had never seen the outside. She had never even seen the sun, because they all feared the radiation poisoning that would come with it. But she wanted to live before she died, not just survive.

Jacinta Wallace was born underground. She was a fourth-generation Mount Weather inhabitant. Expecting that she would be able to find a way to survive on the surface was laughable. But tomorrow would be her eighteenth birthday – the eighteenth cold year she spent underground, and the fifteenth year since her mother walked out into the sunlight because she wanted to experience the real world, even if it cost her life.

We need to live real lives, not just survive down here. Those had been her words, and as small as she'd been, Jacinta could remember them perfectly. Her mother Nessa had been restless – yet another thing Jacinta had inherited from her, as well as her glossy auburn hair and startlingly blue eyes.

But on her eighteenth birthday, her entire world was thrown into uncertainty, starting from the moment that her dad woke her up. It was still dark, far too early for Jacinta to be waking up on her birthday, of all days. She opened her mouth to tell him so, but Cage Wallace held up his hand for quiet, and when the head of security wanted something, even his daughter knew to fall into line.

"We can talk about birthday stuff later. The most important thing is that you're an adult now. It's time to show you what being an adult means."

Baffled, Jacinta pushed herself up from her bed. No 'happy birthday', just this? Usually her dad was more accommodating, but his dark eyes were gleaming and she could tell that he meant business. Licking her dry lips, she grabbed a jacket and pulled it around her shoulders. Despite having lived in Mount Weather her whole life, that was something she seemed unable to acclimatise to: the cold.

As a small child, she had followed Cage down most of these corridors. Often, she would go to her grandfather, President Dante, and watch him paint, although she didn't have the knack for such art herself. That had always been Jacinta's way. Quiet and observant, but inwardly restless. Craving things she had no right to want, and no possible means of ever having.

Cage swiped his access card at a door, stepping inside before ushering for Jacinta to follow. Her eyes being so used to the bright fluorescent lights of the corridors, it took a moment for them to adjust to the darkness that she was met with. But once she was able to take in her surroundings, Jacinta had to fight back a scream. Two people were hanging upside down from vices, blood pumping out of their bodies and into clear bags.

It wasn't the worst of it. As she followed her dad into the dimly-lit room, she saw rows upon rows of cages. The prisoners kept inside stared at her with feral eyes, savage anger. Grounders. She had seen a few of them before, but not like this. She went to kneel in front of one of the cages, before her dad grabbed her arm and hauled away.

"Don't go near them, Jacinta."

"But…what's happening here?" Her voice was barely above a whisper as she tried to make sense of it. The imprisoned Grounders, the unconscious ones having blood drawn from them a little at a time…she didn't understand it. It frightened her, both the darkness and the fact that there was something going on behind locked doors that only now her dad saw fit to tell her about.

"The Grounders can survive outside, in the radiation." Cage gestured to the ones hanging upside down. "We can't. When people are exposed to radiation, they are given a treatment to help them heal. What do you think is in that treatment, Jacinta?"

She didn't need to guess, for she knew the answer with cold certainty now. She had of course seen the treatment in effect – Dr Tsing would administer a mysterious 'treatment' to radiation sufferers. Jacinta had asked about it, as a child. The doctor had smiled patiently and replied that it was a mix of medical ingredients that wouldn't make sense to someone who hadn't studied medicine. The truth was far simpler, but far more horrible.

"Don't you want to go outside, Jacey?" Cage gripped his daughter by the shoulders and turned her to face him, his tone affectionate and his use of her childhood nickname no doubt intended to calm her. "Wouldn't you like to be able to see the world outside of Mount Weather – with your own eyes?"

She did. She would. He already knew that, which was why he was driving the point home. But although the Grounders were vicious and brutal, Jacinta hadn't quite made up her mind about what she thought of all of this. Her mind was still reeling from a truth that most adults in Mount Weather seemed to be aware of. They were all using the blood for radiation, and they didn't bat an eyelid at where it came from. Why should she? Grounders had killed their people before. Yet despite her attempts at self-conviction, it wasn't what she truly believed.

"But this is the cost?" Jacinta asked in a small voice, causing Cage to release her and sigh, raking a hand through his dark hair. He looked down at his daughter with a mixture of despair and resignation.

"You're so much like your grandfather sometimes. You know that?"

Jacinta couldn't help but smile a little at that. "I'm not sure that's true."

"One day, I will be President, when your grandfather dies." Cage observed his daughter, watching as she stepped towards the motionless Grounders. She realised now that what hung before her was an opportunity at survival. But more than that, it was her family's legacy. "You'll inherit that position after me. The first female President of Mount Weather, and maybe even what lies outside it."

Jacinta swallowed the lump in her throat. Her mother, driven mad by the thought of remaining in Mount Weather her entire life, had walked out into the sun knowing what would happen. What if they were to do the same, but with a different result? Was it worth the deaths of countless Grounders so they could have life beyond the mountain they called home?

"Who else knows about this?" Jacinta asked, turning to glance over her shoulder.

"All of the adults, of course." Cage's tone was light and he stepped towards her, clearly seeing that she was shaken. He kissed the top of her head. "I told you, you're an adult now. Happy birthday, Jacey."