‘While the rest of the world begins to lose their memories. A sole teenager starts to learn things about the world that they had never dreamed of.’

The original premise look eerily similar to the novel "The Giver" that is being made into a movie with Jeff Bridges.
For those who have not read the book (or who might), Here is the imdb URL: http://www.imdb.com/title/tt0435651/?ref_=fn_al_tt_1
Talking about somebody thinking that they live in an ideal world but suddenly discover that they live in a dystopian reality, Personally, I would like somebody to write a story/screenplay set in the "Firefly" environment. A script describing what happen on the planet Miranda where the reavers were created from the perspective of a somebody not affected by the air supply additive.

(almost a year later, but maybe it's still a work-in-progress?)

"A world they never dreamed of."
Who's they? If it's the protag, use he or she.

I'd also love a touch more specifics, to paint more of a picture in my head.

I like the premise, what happens to the teenager or the world because there is one person that remembers?

That's an idea, but not really a logline. It's the setup, but what's the story?

Why is everyone losing their memories?

Tell us about this teenager, what makes them interesting?

Is his quest to discover why this is happening?

You don't have to give us every detail, just a little more than you have.

Right, how will this "lucky" teen save existence and all our memories??

Then what? What is the character's goal?