Hotch (Thomas Gibson) and the rest of the squad will square off with a host of new villains when the CBS series "Criminal Minds" returns with its eleventh season.

TV Line reports that the upcoming installment will kick off with an investigation of a network of hit men called "The Dirty Dozen." Showrunner Erica Messer said in an interview that the case will be especially difficult for the team, as they also have to deal with problems within the department.

"This, in addition to the "mole" plot, will keep Hotch and team on the edge until the last episode of season 11."

Apparently, this plot will not be concluding in episode 1, which means viewers will get to follow the story arc of the criminal network until the finale. Meanwhile, the mole in the Behavioral Analysis Unit (BAU) has been revealed when Hotch expressed his misgivings in the trailer released by CBS.

In the clip, the agent can be seen telling the rest of the gang that he has a bad feeling that one of them has been tipping the serial killer they are tracking. The UnSub has a curious way of killing his victims. The murderer overwhelms his target then injects them. Once incapacitated, he will then perform some weird stuff, which includes painting their faces.

Hotch believes that the reason they cannot apprehend the suspect quickly is because an insider in BAU is feeding him information regarding their strategy. This mole is reportedly very much involved in the investigation, thus privy to the classified details about the case.

Meanwhile, Messer revealed that season 11 will witness a more serialized, episode-by-episode approach. She said that this new approach in storytelling will add more excitement and suspense to the series. Matthew Gray Gubler, who plays Spencer Reid, expressed his excitement about the change, saying that it was "a crazy arc."

Gubler also teased that the upcoming installment will be a rollercoaster of emotions for all the characters. The actor said, "It's exciting, spooky, team members might be in peril. Fun stuff as always!"

"Criminal Minds" season 11 premieres on Wednesday, Sept. 30, at 9 p.m. on CBS.