More knowledge has been revealed for season 4 of "The Librarians," as plot speculations, as well as a new release date, have surfaced.

As per the upcoming season's official synopsis, characters in "The Librarians" will once again be off on adventures to save the world. The heroes of the series will be squaring off with Americal Civil War-era ghosts, saving the town that they are haunting, tackling Santa's brother, the Patron Saint of Thieves, dealing with a casino which apparently steals their customers' luck, solving a body-switch in one episode, and working with a Librarian from the past.

A trailer for season 4 has also revealed a peek at what fans should expect, such as an impromptu wedding between Flynn (Noah Wyle) and Eve (Rebecca Romijn), the Library being lost in the ether of reality, imprisonment in a monochrome film noir movie, and people with laser beams used in a lightsaber battle.

The series will also take after the events of season 3, where Charlene (Jane Curtin) is no longer tethered to the Library, meaning more anomalies are to be experienced, as the Library's link to humanity is gone. Still, this may not be for long as one Librarian and one Guardian may have to replace Charlene. Flynn and Eve may be the daring pair who are set to be bonded with the Library forever, giving them immortality but restricting them to the place.

"The Librarians" gained much prominence back in 2014 where its peak viewership clocked in at 5.3 million people. The previous run, season 3, only had 2 million but eventually rose up to 5.4 million viewers due to streaming and DVR, hence the renewal for season 4.

Eager fans who are excited for the return of the popular television show will also be pleased to hear that the premiere date for the first episode of season 4 has been moved a week earlier. From Dec. 20, the first episode will now air on Wednesday, Dec. 13, at 8 p.m. EDT on TNT.