Once Upon a Time welcomes the winds from the West tonight and drops a familiar figure to shake up Zelena’s plans. Check out the full preview of “Kansas” here!

Tonight’s all-new season 3, episode 20, “Kansas” will introduce two new characters to the world of Once Upon a Time. One is the key to Zelena’s greatest feat of magic, while the other may bring about her undoing. Dorothy Gale makes her appearance in a flashback, while in the present, Mary Margaret and David welcome the newest Storybrooke resident.

Last week on ‘Once Upon a Time’

Zelena’s plan to enchant Hook’s smooth talking lips is not moving along as quickly as she hoped. The clock ticks on Henry’s safety and Killian tries to ship his young friend back to New York with Mr. Smee. Their plan is interrupted by the arrival of flying monkeys, a sight that sparks Henry’s curiosity regarding his current residence.

All of the memories flood back to him when he touches the storybook and once again recognizes his adoptive mother, Regina. Hook is once again on the fringe of everyone’s trust when the memory curse is wiped away and no one can decipher on which side his true loyalty lies. With their memories intact, everyone learns that Snow cast the curse during the lost year.

This week on ‘Once Upon a Time’

Mary Margaret’s labor is stopping for no one. As the contractions echo through the town, Zelena makes her way to greet the newborn with a kidnapping threat. A balloon arrangement lacks her flare for the dramatic.

Meanwhile, in a flashback, Glinda attempts to convince Zelena to return to Oz and become a guardian rather than an enemy. A storm brings an unsuspecting young girl named Dorothy from Kansas to the strange world.

Watch a sneak peek of tonight’s episode here:

Check out the full set of photos and synopsis here and be sure to check back after the show airs for our recap!

Watch Once Upon a Time season 3, episode 20 “Kansas” tonight at 8 p.m. ET on ABC