Every eight year old gets tested for blood of the ancients. It is not hereditary, it almost seems random. Families that have children with this blood can run. They will eventually get caught and slaughtered in front on their child. Or the family can sell the child and be set for life. Ryl is found to have the blood and is sold by his family.
All children that are found to have the blood are sent to the Stocks were they live out their lives until their harvest time. The harvest time is determined by the amount of Ancient’s blood they have. This way the rich family that bought the child can get the most of elixir from the child. It helps these families live long lives and get power.
They are called tributes. The 200+ guards are there to supposedly guard against outside threats as well as quash any rebels internally. But realistically, they are a sadistic bunch that are being punished for conduct in the regular army. They treat the children poorly and abuse them.
One day as Ryl is working he stumbles into the forest and finds the forest changing. He runs into a man he explains more about his blood and what he must do. He must inspire others since he will not leave except through the front door on his harvest day. That doesn’t sound like much to him (or the reader), but it turns out to be quite the adventure.