The description of the neighborhood, it describes a cold, worn-down, neighborhood, that could symbolize a prison, based on the first sentence that had to do with setting people free. The neighborhood is decribed as stony and "imperturbable" so it could also mean that the school symbolizes freedom and the neighborhood means imprisonment, or capture. Of course, this is only based off f what I have just read, I haven't actually ever read the book.
It is used as a noun clause here. Noun clauses function the same way simple nouns do - they answer questions such as who or what.
So, what is a secret? Where we shall go - it functions as an object.
Answer:
we can be friends (╯ರ ~ ರ)╯︵ ┻━┻