What do you think of my plot?

I was talking to my friend the other day and we got an idea for a story. Essentially, it's about this fictional land where no animals can survive if they live in valleys or at sea level and none of them can live in water (it's a long story). So, there's this Society of humans that live on this huge mountain way above sea level in this mountain utopia. In this civilization are their peacekeepers/soldiers that just so happen to ride dragons or griffins or pegasus depending on their rank and skill. The story follows three members of the guard and this job they get assigned to which ends up sending them as liaison officers to the main land and to establish a treaty. But, they aren't used to the main land culture and other basic crap and have to deal with a ton of racism and adversity. Then, they discover that the liaison officer that was sent to their people tried to murder their king and they try to think of ways to struggle through the accusations and get a treaty signed and passed before their king gets attacked again.