I'm writing a futerristic story I need plot idea?

Depending on your choice of a), b) or c), you'll get different audiences. Also, you can go with different approaches, scientific studies, religious, superpower (unexplained) or magical. Choose what you feel the most confident about writing. If you feel confident about writing any/all of the themes in parallel, go ahead. Two (or 3) books, two environments, same story, different subtitles. Here goes:

My first quarter:
The main character lives a normal life. One night, he falls asleep and he/she (he from now on) shifts bodies with (choose one):
a) another person
b) another animal
c) another being, not limited to Earth.
He realizes this ain't a dream and it happens whenever he falls asleep. Ultimately, he becomes used to it.

My second quarter:
Then suddenly he gets into a body of an insomniac or a being that doesn't sleep. Eventually he makes a long-term promise/pact/falls in love with another ("Another" in the further text).

My third quarter:
He dies. You can totally see it coming, but it's a very shocking and tragic event. Like Eddard Stark's death from Game of Thrones.
Let the story develop and unfold a bit without him. He wakes up. Another body. Turns out it's not limited to sleeping, but losing consciousness. It happened before, in the first third, but nobody payed attention to it to look at it that way.
He spends a lot of time searching for Another. Switching bodies to try to randomly get closer, leaving notes for others, contacting the ones he knew before, etc.

My fourth quarter:
A familiar scent. A dream of the time with Another. A happy/interesting memory...
Scene of Another sleeping. Another wakes up with a jump. Grabs head. Looks at the mirror/lake/metal plate. It's him in the body of that "another"! Is this the ending? How and if it unfolds is up to you :P