My actual passage is a bit involved, but I've had this come up a few times over the years, and I've never resolved the issue. So I'll give a generic passage. I posted this question on ELU but didn't get very far.
Mars, the Red Planet. But to the Romans, he was the God of War! Herein lies the story [?]
Imagine this as a prologue or at the end of a prologue.
A period doesn't seem right. If I use ellipses, three dots or four? If four, ... ., ...., or . ...?