[@Polybius]
The story can evolve further rather easily if you think about it a little.

Perhaps the two celestial bodies are trying to get ever closer to one another, and should they succeed in meeting it would spell the end of the world (Majora's Mask style). 
So the question would be [i]how do prevent that from happening[/i]? 
Perhaps magical institutions who live on the planet and other gods are actively working against this union for... um.. eternity? So that the planet's inhabitants can continue to exist and avoid an apocalypse.
What form do these magical institutions take?
What are their motives?
May this is a perfunctory responsibility they've been dealing with for awhile.

We could get a pantheistic love triangle going too. Maybe some other deity wants in on the action?
You want Olympic Gold Medal-grade drama? We can do that!

Edit; Fine, lol