Plot summary
In a flashback, Regina comes across Drizella, who is looking for magic to escape from her mother. When she reveals that she was actually born with magic, Regina begins to train her. However, after Regina runs into Rumple, who tells her that Lady Tremaine must have been aware of the magic lessons, the two women realize that Lady Tremaine was counting on using Drizella's heart to revive Anastasia. Drizella ends up blackening her own heart by killing the prince, making it unusable for revival, and vows to cast a curse like Regina's to make her mother suffer.
In the present day, Roni struggles with what to believe about the mysterious photo, which is complicated by newly discovered information about "Regina Mills" into which Lucy encouraged her to look. Drizella gathers the ingredients for a plant that the witch then cultivates and, when she serves its essence to Roni, she wakes up and remembers her life as Regina. Drizella then reveals that she cast the curse and blackmails Regina into keeping Henry and Jacinda apart, reminding her of a special contingency that was put into the curse that would hurt her family if she didn't comply.
Credits
Adapted from Wikipedia contributors, Once Upon a Time season 7. HTML formatting and reference markers removed.