One good way to look at a story is to ask, What is the overall goal of the lead character?
In your story, the goal of the lead character is to save her son.
Therefore what sets the story in motion would be, her son being kidnapped.
Now that we know what sets the story in motion we can begin to see a logline. Because that event is what starts the logline.
"When her son is kidnapped, an ex-con trying to go straight, must..." (Then tell us your lead characters plan-but not whether it succeeds or not so you don't give away the ending)
Now we have a beginning, and also, because your lead character wants to go straight, we also have internal conflict because she may have to do illegal things to save her son. (And internal conflict is great)
To review, the beginning and the end of a story should be like mirror images.