The Bridge

Imagine a suspension bridge, like the golden gate bridge. It has two large supports, from which the roadway depends. In story terms these two arches are the points that support your story.

1. The point of no return. There must be a point after which the character can not go back.
2. The big disaster. The moment where not only is there no going back, but all is lost. It's absolutely hopeless. The reader would give up, but the character presses on.