Do you mean "the beginning of the story?" This expression usually means that there is more to tell about something. Sometimes, it implies that there is *very* much more to tell.
Here's a common use of that expression in a dialogue:
Mary: "I went shopping today, but I couldn't find the clothes I wanted."
John: "Oh no! That's too bad."
Mary: "That's only the beginning of the story! When I was going home, I was in a car accident!"
It also literally means the beginning of a story (a book, usually).
"At the beginning of the story, the princess was in the castle. At the end of the story, she lived with the prince."