What Really Happens During a Comatose

Some people believe that when in a comatose your inner spirit wanders the earth until you wake. Some believe you just black out and then you wake up, as if not even a full day has passed. There are many beliefs on what happens when one seeps into a coma. What if none of those are right? What if you actually go to a different world which is the brink between life and death? Three people will go to this world and fight for their lives so they can come back to the living. Will they make it back or just die trying?