I'll give it a try. Community please correct me if I'm wrong. This outline contains spoilers.
Nehrim is a realm on the world of Vyn. The realms of Vyn are reigned by gods, called light borne ones.
After an uprising in Nehrim, god Erodan was killed by Narazul Arantheal. Aarantheal believes, that the gods are no eternal entities, but only extremely powerful magicians, who reign by their will and therefore supress humanity. Arantheal was punished/bannished for that crime by the other gods.
Meanwhile, his former ally, Chancellor Baratheon, used the situation for the acclamation of regency over Nehrim. First of all, he prohibited the use of magic, because he feared that magic might endanger his power.
But Arantheal did not only fight the gods with Baratheon, but also with other comrades. These formed an order and keep on fighting for the ideals and ideas of Arantheal and stand against Baratheon. They try to train young magicians against his rule. This is where the story of Nehrim starts in the game: You are a chosen one, able to do magic and elected to be trained by Arantheal's order.
During the game, you are part of a twisted story, learn about the gods, magic, fate and the connection between them. You become a magician, you find and free Narazul Arantheal, you free the Northern Realm and fight Chancellor Baratheon. With Arantheal, you even fight the gods, only to learn, that there has always been gods and and uprising shadow-god (Tel'Imaltat), to keep the world balanced. This eternal law is enforced by the fate's summoner. By overcoming the summoner, the world is freed from gods and fate of humanity is now in humans' hands.
This is a short wrap-up, I think. I hope, this is what you wanted without telling too much and also I hope, I explained it correctly without forgetting crucial parts.