This Sunday's Once Upon a Time episode will be all about Cora.

On "The Miller's Daughter," viewers will meet a younger version of this mischievous character, portrayed by Rose McGowan, and perhaps get an idea of just what turned her into the villain we know today. To wit, check out this sneak peek:

Continuing in the past, fans may also be shocked (and grossed out?) to learn what kind of relationship Cora had with Rumpelstiltskin back in the day. Let's just say a whole lot has changed since then:

Elsewhere, we fast forward the modern times and see both a wounded Mr. Gold and a determined Mary Margaret. Will she really go through with killing Cora? David sure hopes not:

Finally, break out the Kleenex and watch Gold phone Belle, offering her some words of inspiring wisdom to try and cure her case of amnesia:

NOTE: Visit TV Fanatic tomorrow for an exclusive interview with producers Edward Kitsis and Adam Horowitz as they tease both this installment and what else is to come on Once Upon a Time Season 2.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.