"Strange Case" is the fourth episode of the sixth season of the American fantasy drama series Once Upon a Time, which aired on October 16, 2016.

The Victorian England events take place at an unspecified time, years before Alice is released from the Bethlem Asylum in "Down the Rabbit Hole", this story also takes place after Belle becomes Rumplestiltskin's maid in "Skin Deep" and before Regina tells him Belle has committed suicide in the same episode.

That night at a party, Hyde, with the help of Rumplestiltskin, confronts Mary’s father and threatens to expose the truth about him sleeping with his lab assistant if he doesn’t grant Jekyll his membership into the academy.

When news leaks of Hyde escaping the hospital, this suddenly disrupts the normally for David and Snow, as well as for Emma and Hook, who is ready to move in with her.

As Gold leaves, he tosses Jekyll’s heart back to Regina, who then sends him to the Jolly Roger to stay with Belle.

Gold sought out Jekyll to see if his serum could rid people of "weakness," but when his experiment failed, he angrily banished Hyde to the Land of Untold Stories.

Back at Storybrooke Elementary School, Snow resumes her role as teacher, and introduces her new assistant Shirin to the class.