Roadmap Placement - Why Placement

Should the roadmap come before the heart story or after? I see both when I study famous speeches. I was thinking I would do an "overall presentation" roadmap at the very beginning (very quick - this is my topic - my why). Then do another "head - content section" roadmap after my heart story. Or, does my "why" need to follow my heart story...after they are hooked? Thoughts?