Yes, Abrihet is only a small part of the story, we will see more of her and our favorite gentle scientist later on. Also as a hint; Abrihet is not the unexpected one in the title!
I'm going to take a wild guess and say that the unexpected visitor is the Krytponite bullet.
Really? Who says Lex discovered Clark's secret?
Um... You... in your description of this story.
Description: This is a brief follow-up tying together some my previous vignettes: Ants at a Picnic, A Lovely Smile and The Ring. In this story, Lex Luthor had a brief flirtation with Lois, but she saw through his façade and married Clark instead. For that reason and many others, the billionaire was determined to permanently remove Clark from the landscape of his life.
If I'm wrong, it's only because you led us on a merry red herring fishing trip.