Plot summary
In the past, after teaming up in Camelot, Ruby and Mulan have made their way to Oz in search of the wolf pack. They meet Dorothy just as Zelena returns to Oz after being banished by Regina. Ruby and Dorothy form a bond as they work on a plan to defeat Zelena and get Toto back. In the present, Ruby finds herself in the Underworld after using a tracking spell to lead her to Zelena. Zelena reveals that she put Dorothy under a sleeping curse which can only be broken by true love's kiss.
The heroes believe that a kiss from Dorothy's deceased Auntie Em is the solution but, after Hades ruins their plans, Snow suggests to Ruby that her feelings for Dorothy might allow her to break the curse. Meanwhile, David and Snow get antsy after the phonebooth is removed and they have no way to check up on their son. After Hook is able to change the name on Snow's headstone to "David Nolan", Snow is able to leave the Underworld with Ruby and the two head over to Oz, where Ruby is able to free Dorothy.
Credits
Adapted from Wikipedia contributors, Once Upon a Time season 5. HTML formatting and reference markers removed.