Criminal Minds: Here's What We Can Expect from Season 13

Here's Where Season 13 Picks Up

When last season concluded, several of the BAU members were about to be run over and crushed by a speeding truck. In the premiere episode of Season 13, it will be addressed as to who survived the horrible crash and who did not.

On Tuesday, Messer offered a brief synopsis of what is happening when the show story picks up.

"Garcia [Kirsten Vangsness] has just learned that her team is in trouble. And the first person she calls is Agent Simmons," Messer said while speaking with EW.

"He drives them to the site of the last known signal from the team. They discover this horrific car accident. Once they see who is injured, they discover that someone is missing."

For those wondering who Agent Simmons is, he is one of the characters that were added to the cast in the shakeup. Learn which character he is replacing below.

Damon Guptons Is out, Daniel Henney Is In

A month after the finale, Damon Gupton, who joined Criminal Minds halfway through Season 12, was let go. The network requested that he was added to the show to add an eight character after Thomas Gibson (Aaron Hotchner) was fired, but he was the first to get the boot when making additions and subtractions to the cast.

One week later, Daniel Henney – who Agent Matt Simmons on the show's spin-off Criminal Minds: Beyond Border – was announced to be joining the cast.

"'The discussions were, 'Do you think Daniel would want to join Criminal Minds?' But of course to add one more that means someone's not coming back and that's never an easy thing when someone isn't returning to the show," Messer said.

Eventually, the showrunners concluded that Gupton's character would not be coming back.

Messer continued by saying: "The decision was made that made that Damon would not be returning and Daniel would be joining, so then it's up to us to tell the stories and have them make sense."

Within the show, the character that will be having the most difficult time trying to "make sense" of it all is Paget Brewster's, Chief Emily Prentiss.

Paget Brewster Is Now in Charge

Last season, Brewster agreed to return full time. Her character is now in charge of the BAU now that Gibson's Hotch is out of the picture.

With the new cast, Brewster says that Criminal Minds is in "a wacky place," but she is "really happy to be back."

Not only is it a tough situation for Brewster's character, but also for her as an actress to see some of the former cast members leaving.

"It's always hard when someone is gone, whether by choice or not by their choice... but you roll with it. ... You can't not miss the people who are gone," Brewster said while talking with TV Line at San Diego Comic-Con.

Brewster first appeared on Criminal Minds in Season 2 on an episode titled "The Last Word." While she has been a fan favorite for years, she hasn't been involved quite as long as Kirsten Vangsness (Penelope Garcia) and A.J. Cook (Jennifer "J.J. Jareau) have. While there were talks that Vangsness and Cook may not return, the two officially agreed to come back after getting a pay raise.

A.J. Cook and Kirsten Vangsness Are Back

For a period after Season 12 ended, it remained unclear if A.J. Cook and Kirsten Vangsness were going to return or hold out for more money. They are two of the original cast members for Criminal Minds and it would have been a devastating blow to the fans if they were to opt out of their contracts.

The two actresses were seeking contracts that were on par with the amount that their co-star Matthew Gray Gubler (Spencer Reid) was making. Their new deals essentially give them parity with their male co-star.

This isn't the first time that Vangsness and Cook have held out for bigger contracts. In 2013, the two took a stand during negotiations after they had been paid less than half of what their male counterparts, Gubler and Shemar Moore, made. In the most recent dealings, the actresses threatened to depart from the show if their demands weren't satisfied.

Now that everyone can exhale a collective sigh of relief about Penelope and J.J. coming returning, fans may be wondering: who is left on the series?

So Who's Left on 'Criminal Minds?'

Even with Henney, Brewster, Vangsness, and Cook all confirmed, there are a handful of other series regulars that have agreed to return.

Criminal Minds vets Joe Mantegna and Matthew Gray Gubler signed new contracts back in May. Also joining the cast as series regulars are Adam Rodriguez and Aisha Taylor.

Even with this star-studded lineup, many fans have been missing Shemar Moore's, Derek Morgan. According to the actor, he isn't completely ruling out the possibility of returning to the show.

"Anything's possible," he told TV Guide. "I told all the fans, I keep telling them those elevators closed and they can always open up again."

Overall, the cast has changed with BAU members being added and pulled away from the show for every season since Season 9.

Criminal Minds will return to CBS for its 13th season on Wednesday, September 27.