In Fairy Tale Land, Jefferson takes Regina to meet a man from another land, a doctor, who we recognize as Dr. Whale. He claims to be able to revive the dead, but he needs an enchanted heart, like one plucked from a person’s chest the way Rumplestiltskin showed Regina how to do, to complete his operation. Regina takes the doctor and Jefferson to her mother’s vault which is full of throbbing, enchanted hearts stolen from poor souls all over the land. They choose one and the doctor sets to work. Regina had used a spell to preserve Daniel’s body and thing appear to be going well. Lightning strikes the doctor’s tent, but he soon emerges, sadly admitting that he failed. Regina, heartbroken, returns to Rumplestiltskin and eagerly plucks the heart from another student’s chest, crushing it. She’s ready for her next lesson.
Sometime later, we see Rumplestiltskin meeting with the doctor and Jefferson to conclude their business. The whole thing was a ruse to get Regina beyond her heartbreak so that she could continue her training. The doctor leaves for his world with an enchanted heart as payment, convinced his science is superior to magic and that his process for reviving the dead will indeed work to bring his brother back to life.