Drug overdose will rock the Windy City in the upcoming episode of "Chicago P.D."

Titled "A War Zone," "Chicago P.D." season 4, episode 5 will follow Voight and his team as they arrest the most notorious criminal in the city.

Based on the official synopsis for the episode, the entire city will be on high alert following several cases of fentanyl overdose. As Voight and his team conduct an investigation on the matter, their search will lead them to an infamous crime lord. They will also discover that the drug lord has already managed to escape the citywide manhunt of the police before.

"The team hunts drug dealers selling fentanyl, which has been linked to multiple overdoses around the city; and Tay and Burgess discover a bloodied child who shares a twisted secret about his home life. In other events, Mouse contemplates reenlisting in the Army, and Platt informs Tay about her next assignment," reads the synopsis on TV Guide.

In the promo for the episode, Voight cannot wait to nab the criminal. He tells his group to be vigilant and ensure that the felon will not get another chance to escape. But while he is confident that he will finally be able to get his hands on the criminal, something will go terribly wrong.

The teaser shows that the drug lord has set up a trap for Voight and his men just when they are about to close in on his supposed hideout.

"Chicago P.D." season 4 airs every Wednesday, 10:00 P.M. on NBC.