“Chicago P.D” Season 4 returns in the fall with more drama and romance as the police officers try to keep the streets of Chicago safe.

Voight

In the Season 3 finale, Hank Voight (Jason Beghe) lost his son to a murderer. Through his grieving process, he sought his son’s killer and shot him.

While the officer’s rage might have cost him a possible promotion as the head of intelligence, he may have gotten caught doing the wrong thing by one of the other cops in his unit.

Lindsay

Erin Lindsay (Sophie Bush) saw Voight burying the person that looks like his son’s killer. Did she find her mentor committing vigilantism?

If what Lindsay saw is true, then it will put a strain on their relationship because she has seen Voight as someone to lean on. When she hit rock bottom in the Season 2 finale, he was there to pick her up, helping her to not continue on a downward spiral.

If his way to cope with his loss is to turn to self-destruction, then all the things he said to help Lindsay with her loss all meant nothing to him.

After losing her trust in Voight, Lindsay is forced to turn to Jay Halstead (Jesse Lee Sofer) for comfort.

"Jay is really the one person that she has in her world that she can trust who is safe," Bush tells Entertainment Weekly. "That finale moment with Voight is a reminder that while Voight has been a stabilizing factor in her life, at this moment he is not stable, he's not a person who is going to bring any safety in her world.”

Lindsay is happy that she has Halstead to turn to, especially at a time when she needs him the most.

“Jay has her back,” Beghe says. “Jay also is such a good guy and such a good cop; she really needs that right now. It's no small thing for her to have him to fall back on."

Lindsay and Halstead

Meanwhile, Lindsay and Halstead have decided to take their relationship to the next level and move in together.

Will her leaning on him in a time of need bring them even closer together?

Chicago PD Season 4 New Cast

And just as Lindsay and Halstead are taking things to the next level, Kim Burgess (Marina Squerciati) and Sean Roman (Brian Geraghty) broke things off.

Now that Roman is out of town, Burgess is getting a new partner.

“Quantico” Actress Li Jun Li will guest star in “Chicago P.D.” Season 4 as Burgess’ new partner Julie Tay. Li may have the option of becoming a series regular.

“Chicago P.D.” returns to NBC on Wednesday Sept. 21. Stay tuned.