'Criminal Minds' Is Finally Back, and Fans Are Freaking Out

The 15th and final season of Criminal Minds is back. The police procedural ended its last season with a few unresolved storylines. Among them is the chance that a well-known serial killer who's still at large may be returning to the fray -- and make the life of the FBI's Behavioral Analysis Unit quite challenging. Suffice to say, fans couldn't control their excitement.

"Criminal Minds is back and it's never felt so right," tweeted one viewer, who really captured the sentiment of the moment. "Anyone outside the BAU tends to look suspicious at this point," observed another, while a third confessed that they "watch too much [Criminal Minds] to ever fully be able to live life to the fullest."

Among the swarm of online elation, one of the most-tweeted-about plots was the budding romance between A.J. Cook's Jennifer "J.J." Jareau and Spencer Reid, play by Matthew Gray Gubler.

"I have always loved you. I was just scared of saying anything before, and things are too complicated to say it now," J.J. told Reid in the Season 14 finale. "I'm sorry but you should know."

Cook himself teased the romance between the two characters could be moving forward with an Instagram post back in December but obviously didn't wade into any spoiler territory. More than just a forbidden office romance, as J.J. is married to Detective William "Will" LaMontagne, who's played by Josh Stewart. But that didn't stop the online shippers from rooting for their love, anyway.

The other big one was the possibility that Everett "The Chameleon" Lynch is back to his old ways. Although the sneak peek released ahead of tonight's premiere did seem to indicate that Joe Mantegna's David Rossi might be letting his personal history with Lynch cloud his judgment.

Earlier this month, CBS series' showrunner, Erica Messer, spoke with TVLine about the challenges and opportunities bringing such a long-running story to a close provided.

"Our finale ends up being such a freight train that it was hard to stop and have an emotional beat with a character coming back, but we were able to bring them back in other ways that will make sense once you see the finale," Messer explained about the show's conclusion. "We have this amazing flashback to what I want to say is the season finale of season one, and it just makes me smile every time I see it, because not a single one of the team members is there anymore, except for Reid. It's a nod to everybody who's been watching all of these years."

Criminal Minds airs every Wednesday night on CBS and is available to stream any time on CBS All Access.