In the fairy tale past, a poor, young Cora falls for a young Prince and becomes pregnant, but he turns out not to be a Prince but a gardner and has no intention of marrying her.
Cora and Prince Leopold fall for once another but Princess Ava finds out Cora is pregnant and rats her out. Leopold ends up marrying Ava and Cora decides she must give up her baby in order to have a future.
Zelena sends the Dark One to steal Regina's heart from Robin Hood. When he threatens to kill Robin's son, he has no choice but to give him the heart.
Regina does a spell to summon Cora but it goes awry. Cora takes over Snow's body and shows her what happened in the past. Afterwards, Regina and Snow make amends, now knowing the truth about their mother's complicated past.
Belle figures out that Zelena will use Snow's baby to cast a spell to go back in time and kill Ava, thus Cora will never give her up and Snow, Emma, and Henry will never be born.
With Snow's encouragement to believe in her own resilient heart, Regina kisses Robin.