So I was thinking of making a scifi about earth getting a rather nasty greeting between its first alien encounter and the average human population.

I would love some ideas as to how things go, a conjoined plot if you will. (hopefully I am using the word "conjoined" aptly as I havent the slightest idea what its book definition is).

I already have something in mind but its pretty basic, I would love to add some complexity, excitement, and general surprise.