Alien crown

When you close your eyes, you see the whole world.
There is the Middle Ages. The most serious weapon of a spear and a sword, the best means of transportation of a horse, on the walls of torches and candles, are built of wood and stone at home, sailboats swim around the seas, doctors consider washing hands dangerous to health, the best minds only think about sewage and constitution ...
There you are the heir to the throne of a small kingdom on the outskirts of the inhabited lands.
No, you are not crazy, and this world is as real as your dear. Your memory, mind, experience from here stay with you there, and what you learn there will be with you here. And also, you can take something from that world here, and if you are lucky, something from your world will be with you there when you wake up. There are a lighter, there are a lot of such, but here ... gold. There you are not as much as you would like, but enough to live here well.
So, it turns out you got into a fairy tale?
No, of course. The real rulers of this kingdom are in no hurry to transfer real power to you. No, the ancient treaties will not be violated, and all external decency are observed when the time comes, you will be put on the throne and allow you to try on the crown. But the real rulers of this kingdom will never give you real power. And, as soon as there is someone more convenient for them, they will give the crown to him, and death awaits you. And who knows how to reflect death in that world on you in this world?
Who should you be there, in that world? A stranger doll in a strange crown, living his last days, or a ruler deciding his fate?
It depends on you