Our protagonist (we never learn his name) finds himself walking in a sprawling city with no people. The dim light state sunset is only minutes away, but after hours, evening never comes. After a flying bus-ride, he finds himself in completely new country, a place so real he appears as a ghost in comparison.
This solid place is Heaven.
The Gray Town is Hell.
While the ghostly people spread over the field, several solid people arrive with one mission: to convince the ghosts to remain in Heaven instead of returning to Hell.
After the queen of the SandWings dies with no clear heir, war has ravaged the island. Many tribes railing behind their favorite candidate, but there is no victor in sight.
Then a prophecy comes to light: five dragonets will stop the war.
The Five Dragonets of Destiny—Clay, Tsunami, Starflight, Glory, and Sunny—live in hiding under the mountains. Talon of Peace stole their eggs to fulfill the prophecy and train them. After escaping, they travel to different kingdoms on their quest to end the war.
Wings of Fire' Series Overview Video (YouTube).