What effect do these lines have on the reader?

These lines create a sense of mystery and anticipation in the reader. The use of the phrase "hidden world" suggests that there is something secret or unknown that is about to be revealed. The reader is left wondering what this hidden world is and what secrets it holds. The line "a place where anything is possible" further adds to this sense of mystery and anticipation, as it suggests that there are no limits to what can happen in this hidden world. The reader is left eagerly waiting to find out what lies ahead.