In a futuristic world, high school sports star, Michael, is thrust into spiritual danger when a supernatural force seeks to drive him to fame…but at a deadly cost. Seeking help from the most unlikely source, a new family in town, Mike learns they may be hiding a secret of their own.

The title refers to two things. One having to do with the family, the other having to do with why the supernatural entity is targeting this particular person. It was the only title I can come up with that made the most sense but I could give it another go. It's not an adaptation of anything. The futuristic setting I thought I should have mentioned in the logline but I shall remove it. The deadly cost isn't his soul specifically and telling what the entity wants would completely spoiled everything. The main character doesn't know what it wants and only thinks it would be after his soul but the grand scheme would turn out to be much larger than that and I dont think putting it in the log line would be a good idea... But im new to all this so hows about another shot? Here's the revised version:
"An arrogant self obsessed high school sports star is thrust into spiritual danger when supernatural entity attempts to drive him into fame but at an unforeseen cost. He seeks the help of a religious family new to town, however it seems this family may be hiding a supernatural secret of their own.

I agree completely with Richiev's comment. I have just a question. Why a title "Lost Generation"?
I cannot reconcile the title with the subject. Who is the generation referenced and why lost?
There is a lot of movies and books titled "Lost Generation", unless your script is an adaptation of an already successfully published book I would change to something else.
When I saw the title, I immediately thought of "The Lost Boys" the vampire movie with Kiefer Sutherland and the two Corey's.

There is quite a bit going on in this logline. It doesn't all quite mesh.
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1) I would drop the "In a futuristic world" bit. Not needed.

2) You say, "At a deadly cost" but I would change that to telling us specifically what the cost is. (His soul?)

3) You don't explain why the new family is "The most unlikely source" so I would drop that as well.

How about this.
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"When a demon seeks to lure a devout Christian to success and the trappings that go with it, the young sports star must choose between fame or his eternal soul."
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Hope that helped, good luck with this.