Great,
I get lots of ideas responding to others. So its a rather selfish habit..
The promise is something both LITERAL and Figurative.
All good movies make a promise and pays off that promise. Think of a war movie. The son going off to war saying "good bye ma!" This sets up an expectation that the we will see the son die in action a hero. What we as writers get to do is play with that expectation. Maybe as we get closer to that inevitable scene the son falls from grace, does some very bad things, things that his mother would be ashamed of. Now wracked with shame and guilt the son volunteers for a suicide mission.. get it?
In your story the literal promise of the "mothers return" can be paid off in many ways. The happy ending way: she returns, and we discover that she was FORCED to stay away, and they live happily ever after. or in the not so happy way. She returns, because she needs a new kidney and tries guilt trip her son into donating! (Yeah, its a plot line from Lost) Does the son rebel and refuse, consigning his mom to death? or does he sacrifice and save her, even though she really doesn't deserve it?
The pay off of that "promise" could very well be your hook. And though it seems natural that it would also be the climax of the story, it doesn't have to be.
I don't think a story can be "about' how damaged some one is...
rather it has to be "about" how the damage affects what he does and how he interacts with others.
This may seem like the same thing, but there is an important difference. You cant photograph inner turmoil and emotional damage.
You can only photograph the RESULTS of that tortured mind in action.
A man sitting alone sad, is not a story element.
A man sitting alone rocking back and forth, and cradling a bloody axe, is a story element.
See the difference? There might be a million reasons why the man is sad, but if its all in his head we cant make a movie out of it.
So I ask again, what is your STORY about? (25 words or less
)
If you cant get through the 2nd act, its 90% likely that you don't have external motivation...
Once you know what Michel's GOAL is, and his MOTIVATION for getting there, the 2nd act becomes easy. I'm sounding like a broken record..
Keep at it, and don't be offended if I'm a complete idiot.