Captain Hook (Colin O'Donoghue) has proven himself by facing the impossible on the high seas but in the new "Once Upon A Time" Season 6 Episode 6, he will be going to 20,000 leagues under the sea. Can Hook survive the challenges that await him?

Vine Report featured a new promotional clip for Episode 6 that shows someone poking Hook and welcoming him on board. When he wakes up he realizes that he is in a submarine and he tries to lash out against his captors and tries to find a way out of the situation.

The clip ended by introducing the upcoming character, Captain Nemo (Faran Tahir). Nemo can be seen talking to Hook asking him for his help in accomplishing a mission.

It was reported that "Once Upon A Time" Season 6 Episode 6 will look into Captain Nemo's backstory. Nemo is the iconic captain from the classic novel "Twenty Thousand Leagues Under the Sea." Nemo is said to be a very complicated character.

In "Once Upon A Time" Season 6 Episode 5, Emma (Jennifer Morrison) asked Hook to hide the shears in the ocean. She told him that she will only use them as a last resort in case they can't find a way to get out of their current situation.

Meanwhile, in the official synopsis for Episode 6 as reported by CarterMatt, Emma will try to convince Aladdin (Deniz Akdeniz ) to work with Jasmine (Karen David)  in order to help Agrabah. On the other hand, Regina (Lana Parrilla), Snow (Ginnifer Goodwin) and David (Josh Dallas) will team up in order to save Archie (Raphael Sbarge) from Zelena (Rebecca Mader) while the Evil Queen tries to sow suspicion between Henry (Jared S. Gilmore) and Hook.

"Once Upon A Time" Season 6 Episode 6 titled "Dark Waters" will air on Oct. 30 on ABC. 

Tags: Once Upon A Time Once Upon a Time Season 6 Once Upon A Time Spoilers Once Upon a Time Season 6 Spoilers