If You Give Me a Chance

After escaping from Purgatory, Castiel decides to dedicate himself to helping the Winchesters on their hunts. He wants to become a hunter so that he can work with them. Sam and Dean agree to this and begin to train him to become a professional hunter. The big change may cause many opportunities to open up, specifically for Cas and Dean. There may be many big changes in routine or even bigger changes in relationships.