Jim Gordon, played by Ben McKenzie, was able to achieve a small victory by the end of last season. However, it seems that peace will be short-lived in Gotham, as a long line-up of villains will be making an appearance in the upcoming season.

Gotham's season two has been labeled as the "Rise of the Villains."

The show recently unveiled a trailer which introduced to viewers the villains set to create havoc in Gotham when the show returns for its sophomore season.

Season two's storyline will reportedly focus on a "new formidable villainous duo."

James Frain and Jessica Lucas have been cast as season two regulars. They will play brother and sister, Theo and Tabitha Galvan. Tabitha also goes by the name Tigress.

The duo will appear to be altruistic at first but have sinister plans brewing underneath. They are both set to create more chaos in Gotham this season.

Viewers should also watch out for Jerome Valeska. The first season revealed numerous hints about his role but season two might finally see how he transforms into iconic villain, the Joker. The released trailer also showcased his infamous grin and laugh.

"That's the big focus of the beginning of the season. We're going to tell the story of how the Joker came to be," Executive Producer, Bruno Heller, said.

Season two will also adopt a new narrative style. The show aims to create a better narrative for the origin stories of the villains.

"I think we made a mistake early on in trying to introduce a villain and take care of that villain in one episode. The audience really wants to understand who these people are and live with them, sit with them and enjoy them," McKenzie said.

It seems that viewers will be entertained by villains all season long. The trailer also featured the villains Penguin (Robin Lord Taylor), Edward Nygma, who will become the Riddler (Cory Michael Smith), Cat (Camren Bicondova) and Robert Greenwood (Dustin Ybarra).

Gotham will also continue to tell the story of Bruce Wayne. Season one ended as Alfred and Bruce discover Bruce's father's secret at the end of a dark tunnel. The tunnel has been confirmed as the "Bat Cave."

The upcoming season will also introduce the new Police Captain, Nathaniel Barnes. Michael Chiklis has been cast as a series regular set to portray the no-nonsense and tough Police captain. Barnes is also said to become a mentor for Gordon.

Nicholas D'Agosto, who portrays the charismatic Harvey Dent, has also been promoted as a series regular. He is bound to get more storylines in the upcoming season. However, viewers will have to wait to see his transformation as villain Two-Face. The transformation doesn't happen until Bruce Wayne's adulthood.

"Gotham" season two will premiere on Sept. 21, Monday, at 8 p.m. on Fox.