First, I feel your pain. It's hard to find Castiel or Nathaniel and when you do, Castiel yells at you or tells Nathaniel to 'act like a man' (depending on your answer) and Nathaniel responds with 'If he was a man, he would do his responsibilities' bla, bla, bla.
Anyway, first off try to stock up on APs. If you log on EVERYDAY you get 10 APs each day. Try to do that for four or more days so that way you have at least 40 action points to spend. (As well as 40 bucks.) Afterward, alternate between going to the courtyard and hallway/student counsel room. You should encounter one of them, and the rest is up to you. (P.S- If you insist Castiel sign, he'll yell at you. I felt bad, but later on so does Nathaniel. For you, I mean. He blames Castiel. ^-^)
Experience and tutorials from the Moderator.