Ra retired thousands of years ago, when he decided that would be safer for his pantheon and the human world. He still believes that, but a series of natural disasters pull him away from peace. He worries that his enemy is breaking out of the underworld, and if that happens, it will only mean one thing—war. Ra will do what he can to prevent that, and in the meantime, maybe it's time for him to see what he'll be saving.
Frey is a minor god in his pantheon, and he likes things that way. After exposing himself to Odin's wrath by helping save Loki, he moves to Finland, hoping to find peace. He does, but he also finds Ra, one of the most powerful gods of the Egyptian pantheon, wandering around.
Frey takes Ra under his wing, but they can't ignore what's happening outside their corner of the world even as they fall in love. Frey is having visions of a giant snake, and Ra knows exactly who it is. Together, they'll have to find Apophis's ally to stop the natural disasters, but even if they do, it'll only be the beginning of the fight.