Welcome to the Wicked West, Once Upon a Time Fanatics.
On Once Upon a Time Season 3 Episode 16, Zelena will first shock Regina with the pair's unexpected familial relationship... and then she'll challenge the Evil Queen to a duel in the street.
If Regina refuses? Zelena has a certain (dark) card up her sleeve that she threatens to unleash on all of Storybrooke.
Watch a pair of clips from the upcoming installment now and prepare for one serious sisterly showdown:
Elsewhere during the episode - back in the past in the land of Oz - a jealous Zelena asks the Wizard to send her to Fairy Tale Land after discovering the truth about Regina ... and also after learning that Rumplestiltskin is training her to become a powerful enemy.
Watch Once Upon a Time online if you need a refresher and click through photos here from "It's Not Easy Being Green."