HBO finally released the full trailer of "Girls" season 4, a couple of months before the season debuts on Jan. 11, 2015.

The trailer shows how Hannah Horvath (Lena Dunham) starts a new life in Iowa to join a prestigious creative writing course, leaving behind Adam Sackler (Adam Driver) and all of her friends in New York City.  Hannah is surprisingly optimistic at the beginning of the trailer.

"Honestly, I feel like I made the right decision, which is a totally new sensation for me," she says.

She also tells Marnie Michaels (Allison Williams) that Iowa is a nice place and they should all move there together.

While Hannah is trying to establish her new life in a new place, her relationship with Adam is still unstable. Back in season 3, the couple finally got to terms with their relationship. Yet Hannah's decision to enroll at the Iowa Writers' Workshop while Adam stays in the city to follow his dreams of landing an acting job in Broadway could possibly take a toll on their relationship.

Elsewhere, Marnie will try to take her musical career on a more serious level with Desi (Ebon Moss-Bachrach). However, things might go beyond a professional relationship between the two, even if Desi is still seeing another woman.

This could be a problem for Ray (Alex Karpovsky), who is still hurting after Marnie decided to stop their friends-with-benefits set up. A lot of tension will be seen between him and Desi this season.

Other things to look forward to in "Girls" season 4 include Shoshanna's (Zosia Mamet) struggle with her parents after they arrive in New York, as well as the roster of guest stars who will appear this season, such as Gillian Jacobs, Zachary Quinto, Peter Mark Kendall, Desiree Akhavan, Jason Ritter, and Natasha Lyonne.

Also, Hannah's gay best friend Elijah (Andrew Rannells) will be heading to Iowa to help her make a very important decision. There will also be a pretty graphic birth scene that fans of the show should be excited to see in season 4.