Twilit Future set in an alternate distant future in which Link vanished after pulling the Master Sword from the Temple of Time, allowing Ganondorf to continue his rule of Hyrule indefinitely. Eventually, a new city was created in a land beyond his influence, established by the remnants of the Hyrule royal family. It was built inside a kind of horse-shoe shaped range of mountains, making it very well-fortified. Eventually, both sides developed megabombs (equivalent to nuclear weapons), and ultimately ended up blowing each other to kingdom come. Having foreseen the possibility, a company run by the royal family, called Hy-Tech, developed vaults to keep a number of people safe-but also to run certain experiments, some social, and others technological. You are from the Kokiri Vault, where no one physically ages past ten years. Of course this is about to change... Twilit future is set in a unique sort of hybrid universe of Legend of Zelda and the Fallout series.
Saria's face, first from when she's a "child" in the vault, the second from when she becomes an adult.