[s2e8] Into The Deep Official

To enter the Netherworld, Mary Margaret initially goes to sleep, but eventually, David must be put under a by Regina and Mr. Gold to reach her.

You can find this episode on streaming platforms such as Apple TV or Disney+. "Once Upon a Time" Into the Deep (TV Episode 2012) - IMDb

: Cora kidnaps Aurora to use her as leverage and does everything possible to secure the compass to find a way to Storybrooke.

: Mary Margaret and David use the Netherworld (a realm between sleep and wakefulness) to communicate. The Sleeping Curse :

Allied with Emma and Mary Margaret; Aurora is kidnapped by Cora.

Protecting the compass and her mother in the Enchanted Forest. Voluntarily enters a deep slumber to contact David. David Nolan (Prince Charming) Takes the sleeping curse to save Mary Margaret and Emma. Cora The primary antagonist seeking the compass. Mulan & Aurora

: Cora attempts to steal the enchanted compass from Emma and Mary Margaret in the Enchanted Forest, while David puts himself in danger in Storybrooke to communicate with them. Key Plot Points

Reluctantly work together to help David reach the Netherworld.