The rising action is the part of the plot diagram in which the action really begins to pick up speed. Things are beginning to happen quite quickly. "On the eighth night, I was more careful than usual in opening the door."
The climax is the peak of excitement. When the old man is suffocated and his heart beats no more we are at the climax of the story. "Finally it stopped. The old man was dead."
The falling action is when the story begins "cleaning up" loose ends. We find answers to our questions. "If you think I'm crazy, you will think so no more ...first i cut off the head and the arms and the legs....There was no blood to wash out. A tub had caught it all. Ha, ha!