Chicago Fire season 4 plot: Producer teases changes and new cast; will Casey and Dawson get back together?

The season 3 finale of Chicago Fire left fans with two questions -- Is Dawson pregnant? And, where is Casey?

In the final episode, we saw Dawson taking a pregnancy test, but the results were not shown. She then goes to reveal the results to Casey, who's missing and strip club employee Katia was found dead at his apartment.

Dawson's "pregnancy" sparked speculation that the two could get back together in the upcoming season.

But the fact that Casey's missing also leads many to speculate that he may have been kidnapped, or could on the run fearing that he would be framed for Katia's murder.

Executive producer Matt Olmstead addressed Casey and Dawson's reunion possibility in season 4.

Olmstead told TVLine, "Strangely enough, that's the least of her considerations. The first thought in her head isn't, 'Oh, great. This will bring us back together'. The first thought is, 'OK, I've got to deal with this. And I'm going to go inform a guy that, obviously, I loved... – and she still loves in a sense – but we're not together anymore. So I don't want him to make any decisions based on an external impetus."

He further explained, "She's just too proud. So if there's a point where she believed that he wants back the relationship on his own terms, I think she'd go for it. But this isn't Little House on the Prairie where, I'm not going to survive unless there's a man in the house."

The producer also teased Casey's reaction to Dawson's pregnancy news.

He said, "He'd try to downplay his shock and right away be protective and say, 'Great, what are we going to do? Let's get married. What do you need me to do?' It's not like, 'Whoa, whoa, whoa'. Then [he would] figure out his own feelings about it later."

While Olmstead stated that many changes would take place in Firehouse 51, he sure mentioned that a few new character will be seen in season 4.

He told The Hollywood Reporter: "There are shifts within the firehouse that you're going to see at the end of this season and the beginning of next season in terms of personnel and people having some new roles within the firehouse.

"People get knocked out of their comfort zone a little bit and we see how they react to it", he added.

"We're excited about bringing in a new candidate to the firehouse, which we're going to cast and look for." he said, adding, "It's another opportunity to bring in new blood with the graduation of characters and the Mills character going off. It opens up a spot for a new character — a new candidate — and we're tossing around ideas right now about who that character will be," he concluded.

Chicago Fire will return with season 4 in November on NBC.