By the end of this you will understand where your coins actually live, how thousands of strangers keep one honest ledger with no boss, and why cheating it is a losing trade.
Act 1 ended on a single sentence: the whole city sits on a ledger that nobody owns. You learned the assets, the machines, the players, and the square. All of it rests here.
So we open it. The question you arrived asking is the only one that matters at this depth: if there is no boss, no company, no keeper of the book, how does a ledger with no owner stay honest? Today, the machine.
First, a correction to a picture almost everyone carries. Your coins do not exist as objects. There is no token in a vault, no file in a folder with your name on it.
There is only the ledger. Your balance is a row in it that says this address holds this much. And that row is not stored in one place. It is copied, identically, on thousands of computers around the world at once.
Copying digital things is normally free. You send a photo and you still have the photo; the copy costs nothing and harms no one. That is the whole internet.
Money is the opposite. If you can spend the same coin twice, by sending one copy here and another there, the money is worthless. This is the double-spend problem, and it is the exact reason a shared, ownerless ledger was considered impossible until a nine page paper in 2008 proposed a way.
Here is the move that sounds too simple to work. Nobody owns the book because there is no single book. Every participant keeps a complete copy, and the network treats the version most copies agree on as the truth.
You are now one of these keepers. Every copy says your address holds 100. Be honest, you have already thought about it. Go ahead and give yourself 1,000.