Here is another short description for ep. 18, airing on April 1 (aka April Fool’s Day): “Emma keeps searching for evidence to prove Mary Margaret’s innocence in Kathryn’s murder; the root of the evil queen’s disdain for Snow White is revealed.”
Guest starring in the episode are Anastasia Griffith (Kathryn is back? Or is it Abigail?), Meghan Ory (Ruby), Tony Perez (The Evil Queen’s father Henry), Barbara Hershey (the Evil Queen’s Mother), Giancarlo Esposito (Sidney), Alan Dale (King George), Noah Bean (The Stable Boy), Richard Schiff (King Leopold), and Bailee Madison (Young Snow White).