A street drug causing euphoria and then death is slated to sweep through Gotham City in an upcoming episode of Fox's Gotham.

Gotham Villain Oswald Cobblepot Goes To Surprising Lengths To Gain Power

Fox has released a plot synopsis for the fifth episode of Gotham, titled Viper. Detectives Gordon (Ben McKenzie) and Bullock (Donal Logue) will be searching for the source of the drug in the episode.

"Gordon and Bullock search for the source of a new street drug that causes euphoria then death," the synopsis reads. "Meanwhile, Oswald Cobblepot [Robin Lord Taylor] works his way deeper into Maroni's (guest-star David Zayas) inner circle and Fish Mooney [Jada Pinkett Smith] continues to plot against Falcone [John Doman]."

Gotham Season 1 Features Rise Of The Penguin, Is The Joker Coming Soon?

The episode is scheduled to air Monday, Oct. 20 on Fox.

The first season is charting the ultimate rise to power for Oswald Cobblepot, the man who would eventually become The Penguin. His grand return to Gotham after being tossed in the river by Gordon will be a significant one, according to a new report by E! Online. The report warns, "We're not exaggerating when we say that his big, grand entrance will make you scream. Out loud. At your TV. Warn your roommates and family members now, because you won't see it coming!"

Oswald has already exhibited some shocking behavior so far in the series, including viciously attacking two men who pick him up on the side of the road and joke that he walks like a penguin. Fans should expect even more brutality from the villain in future episodes.

Gotham airs Mondays at 8 p.m. ET/PT on Fox.

Watch the promo for the next episode of Gotham below:

Tags: Gotham television fox