School was back in session for Snow White, who went back for her first day as a teacher in quite some time, a return to "normal." She met her new TA, who happens to be Princess Jasmine, but she realizes that she's lost her knack. With advice from Jasmine, she gets her teaching back on track.
Rumple cut his hair, and in an attempt to keep Belle from Hyde, cast a spell on the Jolly Roger that prohibits her from leaving.
In a flashback, it's revealed that Dr. Jekyll created a serum to separate a man's inner beast. When he hit a roadblock, Rumplestiltskin showed up to help him finish it, essentially creating Mr. Hyde.
Dr. Jekyll had a relationship with a woman named Mary. In order to secure their romance, Rumple told Jekyll to use Hyde to romance her. When Hyde told Mary about Jekyll's feelings, Mary told him that she didn't have feelings for him, but instead, that she was attracted to Hyde.
Rumple attempted to kill Hyde, but failed because Hyde was a step ahead of Jekyll.
In the end, Jekyll turned the tables by attempting to kill Belle, revealing himself to still be dark inside. Hook was able to rescue Belle in time, and kill Jekyll, which also killed Hyde.
Rumple confessed that he went to Jekyll and Hyde to begin with in order to separate his own darkness in order to earn Belle's love back when they first met.
Regina asked Emma to do whatever it takes to keep their family safe in the event of her darkness taking over.