The girl is an "avatar" a person who can use all four elements though she pretends to only be an Earth elemental because her hair is naturally brown. Avatars are extremely rare. There are only 4 in this country. One is a grown man working against his will for a company called Assei which a man named Sennai runs. Assei recently rescued another avatar, this one a boy only 4 years old who was at a special school where he was actually a test subject and set to be cut open and studied once he was old enough to keep alive during the operation.
The grown man, an ex-mercenary, is very good and very experienced at using his powers. He easily rescues the boy and takes him back to Assei where he will be cared for and raised to be an agent of Assei. The boy clings to the man like a son. Which doesn't surprise the other agents. They haven't told the grown man of their belief.
Assei believes that there is an avatar bloodline and that the man is the father of all the avatar children currently in the country. Including the teenage girl and the teenage mercenary in the adventuring party. There are Earth, Air, Fire, and Water elementals although water elementals are rare in this country. Most of these all descend from the same bloodlines. Earth marrying earths and so on it is only when two differing elements come together do you get a surprise. Because of this Assei's belief that the grown man could have sired the two teenagers and the small boy are not too far fetched especially since he traveled greatly and slept with many women as he passed through. Assei knows of the two teens but has not been able to locate them yet. The teens know of Assei and avoid the place as they do not want their freedom curtained although they know the company would protect them.
The adventuring party is despairing not that the party is cut into. There is not enough people to go on and the side that is trapped at the beginning is angry to be denied the treasure. The old man looks at the girl like he wants her to break down the door but she knows she's not strong enough and grips a sledge hammer tight. Is it the boy's hammer? She doesn't know. But suddenly the bullet which juts halfway through the door begins to move. Slowly but surely it is beginning pulled away from the door by the boy on the other side's immense strength. When the bullet is clear the girl swings open the door and he lets the bullet fly to smash into the opposite wall. The parties are reunited and continue on excitedly.
The boy stops the girl from following. He has a box of things that must be burnt before they can continue on. As the party moves on to the next room he leads her back into the previous room and asks her to get the flame going. She does so nervous afraid that he will see the flame react to her and know she is an avatar. At first she doesn't notice that he has pressed so close behind her. She is willing the fire to catch slowly and normally when it suddenly begins to burn brightly at the exact second he wraps his hands around her hips and pulls her back into him. She knows the flame does not burn in her control but his. But none save a Earth elemental could have been strong enough to move that bullet. He is an avatar and somehow, maybe because of her very fear, he knows she is one as well.
He caresses her hips and kisses her neck and she is scared but relishes the contact. Meanwhile the fire burns before them as her pulls her back into him and caresses her body. She quiets the fire and moves it to a metal pan. She turns in his arms and begins to kiss him tentatively.
But the husband of the married couple who hired the teenage mercenary comes looking for them and they try to hide but he finds them and then Assei agents show up. The girl and boy are holding hands pressed against the wall and their bodies have regressed. The boy now appears to be about seven while the girl looks only slightly older. The female Assei agent sits down close to them and says, "You know you're brother and sister right?" There is the feeling Assei was watching them and only rushed in when they thought they might come together romantically. Is the married man an Assei agent?
The boy stiffens at the thought they might be siblings but the girl looks down at their entwined fingers and their dirty ragged fingernails and only thinks that she loves hm and doesn't want to be alone. They run thought the house and somehow mange to break open a window quietly and escape.
Hding against the side of the house an Assei agent comes around but they hide her into the ground so that she looks up at the Assei agentman. The agent feels the grass is warm and knows they were here recently. He yells to someone behind him and walks on around the corner of the house.
The girl emerges from the ground and looks up to see the boy had thrown himself onto the roof. They see the Assei building in the distance and think of the safety there but they are scared. An Assei agent air elemental spots them and gives chase. The girl blasts the agent woman with air but the woman shrugs it off. When actively using the element their hair and eyes turn white and two white spots appear on their foreheads.
The girl has revert to even younger now that she's scared although she had been returning to her proper age she had only gotten to around 13 before confronting the agents and reverting again. Because of their small size the two avatar children have trouble making it over fences and running but the girl knows the area and runs to a friend's house. The friend has a secret entrance and lots of alarms and traps and while there they rest and almost start to grow again. Then they hear the agent woman trying to blast the door down.
They prepare to run and the avatar girl opens the door and calls on fire, causing her hair, eyes to turn red-violet and two spots of the same color to appear on her forehead. Blasting the woman with fire in the face while she stands at the top of a ladder buys them enough time to get away.
They make it to a park where there's a festival. She tries to hug the boy but he pushes her away saying they're siblings. This hurts the girl but she holds his hand and they go to hide again. Their ages seem to have stalled at around 9. They gather tall grass piles laying around a pass people who are staying under them. Many of them are smoking. They join a large group of children and sleep under the rushes.
The next day their ages have returned to normal. The boy is around 19 the girl maybe 20. Both are skinny, almost malnourished and pale. Neither have had easy lives. He drives a car with the steering wheel on the right. While she sits curled up in the passenger seat. She longs for his touch and affection again but hasn't tried to touch him since her pushed her away. Meanwhile he grows tenser as he drives because now that his brain isn't that of a child's he lusts for her. While she has her eyes closed his eyes trace her full breasts and pale skin. He wants to tangle his hands in her long hair and press himself against her. Maybe she is his sister but they have no way to prove that as they are now. Would it really be so wrong? She doesn't feel like his sister. They weren't raised together. He rationalizes away any lingering concern as he drives.
When she opens her eyes he tells her how much he wants her. She states that he lusts for her but does not love her. He grits his teeth but doesn't deny it. She longs for the contact for the caresses and kisses again and states that she does not care. She points to a dirt road under heavy forest cover. They park at an old campsite and she covers the car in branches to conceal them further. He strips in the front seat then climbs into the back. She strips slower and he adjusts the branches outside to let in more light so he can see her. She does the same. The first time is fast with little foreplay. She was already very wet from the way he had talked about her before they stopped. He is surprised that her hymen is gone when it's obvious she's unused to touch. She doesn't remember losing it. She doesn't remember anything from before her powers manifested when she was a child. He doesn't either. To himself he remembers the way the old man with her had stared at her and wonders if her powers had manifested because the old man had molested her. He's slower the second time. Taking his take to caress and kiss her enjoying her body as much as he can. She is awash in pleasure.
I woke up after that but I think they were found the next morning and taken to Assei.
Assei isn't a evil company. They've done a lot to stablize the elementals relationship in the world. They have been trying to collect the avatars because of a procephy about a very powerful avatar that will come. I'm not sure if they want the avatar to come they seem to be collecting the avatars to prevent such a thing from happening.
None of the avatars they've collected so far have been particularly powerful. The grown man by virtue of being the oldest is by far the most powerful with the most control. The teenage boy is second in both power and control. The girl has fairly good control and can cycle through the elements easier but she is the least powerful. The tiny boy has more power but his control is non-existent. His powers have only been manifest for a month. The tiny boy and the grown man also have no memories of before they manifested their powers. With the grown man that not odd as he is older it's easy for him to forget but they know the tiny boy came from a good family where he was loved very much. Now he no longer recognizes pictures of his parents or siblings at all.
Although they all at first glance look fairly alike a blood test reveals that they're not all related. The grown man and the teenage boy are father and son though the mother is unknown at first. The tiny boy is related to the teenage boy stronger than the grown man. Further testing reveals that they share the same mother but different fathers and the mother is not an elemental at all. The girl is related to none of them and Assei concludes that she is from another country. This relieves the teenagers greatly especially because the girl is pregnant. Abortion is rare here being only performed in the most serious cases. Though Assei worries that this babe will be the child of procephy they do not stop the pregnancy. The child born is another avatar but is no more powerful than his parents. He is not the Procephy Child. This time through careful observation Assei observes the child's powers manifest and his memories from before and surrounding the manifestation are simply gone. Not repressed but gone. He quickly reestablishes a connection with his parents and the other two avatars, his uncle and grandfather but like them never regains his memories.
All the grown avatars now work for Assei as agents. It's not so different form the mercenary work they'd done before and after a few years of working there they are allowed much more freedom. They leave the compound. Buy a house. Live normal lives for the most part. The teenagers now grown get married as they grew to love each other very quickly. They have three more children none of which are The Avatar but are avatars of various power and control. Two girls and another boy. The grown man does not marry but does date and rabble-rouse quite a bit siring two more children over the years. Neither of which are the avatar either and after their power manifests are taken in by family. The tiny boy is adopted by the grown man and grows up much more secure and happy than any of the older avatars who spent most of their lives running before Assei found them.
Avatars in general are not well liked by the general public but Assei has worked to fix that. Their home country states with timid pride that they have a stable growing family of avatars. One of the only avatar "families" in the world.