Jesse Lee Soffer, Sophia Bush Jesse Lee Soffer, Sophia Bush

The body count just keeps rising on Chicago P.D.

The cop drama, which killed off one of its own in the very first episode, will also end its inaugural season with another major fatality. The death will come as a result of the recent secret meetings between the Intelligent Unit's tech and surveillance expert, Jin (Archie Kao), and Voight's Internal Affairs handler,Sgt. Edwin Stillwell (Ian Bohen).

"It hits critical mass in the finale and one of the characters involved in all this dies," executive producer Matt Olmsteadtells of Wednesday's season finale (10/9c, NBC). "Not only do you have an unexpected death in the finale, you know who the suspect is — you know who did it. So there's a major bomb that drops at the end of the episode which is going to have big ramifications going forward into Season 2. That whole story line hits a shattering climax."

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The death will send shockwaves throughout the group, but will hit Voight (Jason Beghe) the hardest. "[It impacts] the game that Voight's playing a little bit in terms of giving internal affairs a little bit of what they want. But was he a dirty cop? Is he a dirty cop? Will he continue to be a dirty cop? Was he ever?" Olmstead says. "It has ramifications because it takes Voight out of his comfort zone — [it's] the one thing in his life and his business that he doesn't have full control over."

Despite the high amount of bloodshed already, particularly the shooting in Episode 13 that seriously injured Antonio (Jon Seda) and killed a lieutenant and two other guards, Olmstead says there was no hesitation about killing off another character. "On a high-stakes show like this, we have to go there when it's appropriate," he says. "It just felt like it was the natural ramification of a lot of people playing dirty pool and someone had to go."

For one member of the team, this loss will just be a small part of their problems. In the season finale, Lindsay (Sophia Bush) will struggle with keeping her past from ruining her future when her old friend Charlie asks her for a big favor. "It's a favor that risks her career, but she doesn't really have a choice because he's in possession of a secret from her past that could derail not only her career but her life," Olmstead says. "She's in a horrible situation."

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Charlie's reappearance coincides with another return from Lindsay's past: Nadia (Stella Maeve), the drug-addicted massage parlor worker and CI whom Lindsay unsuccessfully tried to take in and help sober up earlier this season. "She tries to do for her what Voight did to Lindsay. Can she salvage this character?" Olmstead says. "And it's happening at the same time where her past comes back to haunt her in the form of this Charlie character."

Although Voight may have his hands full, Lindsay will be able to turn to someone else from the team for help. "She leans on Halstead. ... She does go to him with no options," Olmstead says. "She's not quite sure that's the solution because if [Voight] finds out what the real secret is that this Charlie character possesses, it's curtains for her. So with no options, she goes to Halstead and he finds a way to hopefully get her out of it."

Fortunately, during this period of hardship for the entire squad, the unit will get a new addition in the form of Atwater (LaRoyce Hawkins), who was promoted by Voight last week to replace the ousted Sumner. "The natural expectation was that Burgess was going to get it. And we grab every chance we get to make the show not sentimental; and not give the audience what they expect to have happen," Olmstead says. "So she goes back to being in uniform and Atwater's promoted almost by the fact that Burgess kind of blew it."

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Although Atwater's move up was largely because of Burgess' mess-up, Olmstead does not underestimate what he will bring to the table as a team member. "His character has his ear to the ground when it comes to certain neighborhoods and certain criminal activities. So, he has, as do all the people in Intelligence, his own group of CIs and informants that he's been waiting to draw on once given the nod to come into Intelligence. He knows it's his big break. He doesn't want to blow it," Olmstead says. "It's one of the hardest jobs in Chicago as we portray it to be — not only working in intelligence but working in intelligence for Voight."

However, fans don't have to worry about Burgess' (Marina Squerciati) status on the show. "One of the reasons we didn't want her character to get promoted is that she is so great in uniform sparring with Sgt. Platt," Olmstead says. "[The writers] thought, 'We've still got some more time on this. We still have some more territory to go down in terms of those two characters interacting,' which we loved, so we wanted to keep that going for awhile."

Overall, it sounds like (almost) everyone will be back for Season 2. "It's pretty damn near close to what we pitched, and envisioned and hoped for in the very beginning. A lot of times with these shows, you start off and it's not working so you change this radically or lose the personal stuff or try to make it funnier," Olmstead says. "When I look back on this first season, I'm very proud of what we accomplished and we just want to do more of it. So, we're all very excited about Season 2."

Chicago P.D. airs Wednesday at 10/9 on NBC. Catch up on episodes here.