Captain James Fitzjames has been put in charge as Captain Francis Crozier works on getting sober. As the eternal winter wears on the minds of the men, Fitzjames worries his new command is in jeopardy.

"I think, at that point, Fitzjames' great fear is about mutiny, and I think the idea of not being able to trust the men, of a breakdown in structures that have been his whole life, really," says actor Tobias Menzies, who plays Fitzjames.

Go Inside Episode 6 With the Cast and Showrunners

Fitzjames proposes a carnivale celebration to get the men to work together to accomplish something.

"The tradition of a carnivale celebration is actually historically accurate," says Executive Producer and Writer Soo Hugh. "We know that in the Parry mission that they brought some costumes. In Dan Simmons' book, he added another touch, which is that the actual costumes probably came from the Parry expedition... We loved this idea of this sense of tradition being passed down."

What the crew couldn't have expected is the tragedy to come from their night of celebration.

As the men enjoy the party they've worked so hard to put on, one of the men sets out to put an end to the hopeless mission... for everyone.

"At this point, you realize this is going to be a slow spiral down into the nine depths of hell for all these people," says Jared Harris.

Hear what else the cast and showrunners have to say about the tragic events of the carnivale party.

Plus, watch the all-new episode available now on amc.com and AMC apps for mobile, Fire TV, XBox One, Apple TV, Roku and Chromecast.

The Terror airs Mondays at 9/8c on AMC. To stay up-to-date with all the latest news, sign up for the The Terror Insiders Club.