'Gotham' season 3 episode 13 spoilers: Jerome returns to terrorize Gotham City; Harley Quinn to arrive sooner than expected

Darkness continues to prevail on the upcoming episode of Fox's crime drama "Gotham" season 3.

Titled "Mad City: Smile Like You Mean It," next week's episode will see the return of a familiar villain. According to the official synopsis, Dwight (guest star David Dastmalchian) is still on the run from Gordon (Ben McKenzie) and Bullock (Donal Logue). However, he still manages to revive Jerome (guest star Cameron Monaghan) and activate his acolytes around the entire city of Gotham.

The real reason why Selina's (Camren Bicondova) mother (guest star Ivana Milicevic) is in Gotham and her intentions are revealed, while the power play between Nygma (Cory Michael Smith) and Penguin (Robin Lord Taylor) reaches new heights. The duo will also realize that Barbara's (Erin Richards) plans are finally set in place

Fans are still over the moon after learning about Jerome's comeback, but "Gotham" is not stopping there. The Fox drama is introducing its version of Harley Quinn, and her arrival will be sooner than viewers initially expected.

Prior to the premiere of season 3, executive producer John Stephens teased that a Harley Quinn character was in the works. However, considering her appearance in the DC cinematic universe's "Suicide Squad" last year, the creators were a bit unsure of when she would be launched. It turns out that they finally have a decision and the fan-favorite villainess will make her debut before the third season officially wraps up. There are speculations that the plot might be heading to a Jerome and Harley Quinn team-up.

In an interview, Stephens confirmed the character's TV debut. "We might see [her] in Episode 22," he told TV Guide. It is reported that Harley Quinn's character will play a huge part in launching the central storyline of the upcoming season 4. "It's crazy," the EP added.

The third season of "Gotham" airs every Monday night at 8 p.m. ET on Fox.