Steven is a very abnormal teenager with something akin to bipolarity. Not to mention: he has been bored with just about everything in life. One of the few things he still finds pleasure in is running. It's on one of these runs that he finally gets the chance to have a grand adventure. He ends up in Equestria, but something strange and unexpected happens.
He gets two separate bodies to use with his one mind.

There will be a lot of slice-of-life at first. This site just doesn't allow that tag to be paired with the adventure tag.