Here are some scenes from the March 18 episode 16, entitled, "Heart of Darkness." It appears there will be much derring do in this one!
"Mary Margaret hires Mr. Gold as her attorney when Emma is forced to arrest her for the suspected murder of David’s wife, Kathryn. Meanwhile, back in the fairytale land that was, Prince Charming sets out to stop a determined and unhinged Snow White, whose memory is still clouded by Rumplestiltskin’s potion, from assassinating the Evil Queen."
According to an interview in TV Guide, Lana Parrillla (Regina/Evil Queen) says, "You’ll meet young Regina. I look totally different – fresh-faced,
doe-eyed, young, fun, excited about life, in love, and then it just gets
really dark. It’s way before she becomes the Evil Queen." Ginnifer Goodwin adds, "Folks will sympathize with the Evil Queen in ways they’re not expecting."