If you've been waiting for Once Upon a Time to introduce us to Dorothy, the promo for Season 3, Episode 20 (“Kansas”) should make you very happy.

So, what can we expect when Zelena's greatest foe, according to the story books, shows up? We've taken a close look at the promo to see what it reveals.

1. Baby on the way! As we saw at the end of Episode 19, the Snowing baby is coming. Time to celebrate — but also worry. After all, we know that Zelena wants the baby, and she'll stop at nothing to get it. In fact...

2. Zelena on a rampage. As we see at :06-:10 Zelena is determined to get her hands on that baby, even if she has to take down a hospital's worth of people to do it.

3. Hello, Dorothy. At :13, we see Glinda and Zelena meeting Dorothy. Based on the costuming, it looks like this is a flashback. A pretty old one, too, since Zelena doesn't have green skin yet. At :19, on the other hand, we see a green skinned Zelena attacking Dorothy, to make sure the young girl "can't" hurt her. Again, it seems like we're getting a flashback. How will this hook into the main plot?

4. The gang back together. At :17 we see the Emma, Charming, Hook, Regina, and Robin gang on the move again. We love this fighting force. Hopefully they will be able to help Snow and the baby.

5. Hook collapses. At :18 Hook collapses. Oh no! He better be OK.

6. She's melting! At :23 we see Zelena melting! However, since this appears to be a flashback, she must somehow come out of this encounter alive, unlike in the version we know.

Check it out for yourself:

Did we miss anything important? Interpret something wrong? Let us know your thoughts in the comments below!

Catch the next episode of Once Upon a Time on Sunday, May 4 at 8 p.m. ET on ABC.