a hero—whoever he might be—abandons his safe haven and pushes forward into the wilderness (or depths) in order to test himself against the odds; in the course of this testing, he either discovers his own rich resources or comes into contact with higher powers that assist him. The story inevitably involves a returning, which completes the cycle: the point being that, upon returning, the hero has been immeasurably strengthened by the knowledge gained in the course of his difficult journey.
