Fans of "Criminal Minds" witnessed an exciting premiere episode for season 12 this week, which saw the infamous Mr. Scratch returning as the Crimson King. While the serial killer managed to escape the Behavioral Analysis Unit (BAU), the team found a good one to fill Derek Morgan's shoe: FBI's Fugitive Task Force leader, Luke Alvez.

In next week's episode, the focus will shift from Hotch to FBI Agent Jennifer Jareau as she deals with a rough case.

The official synopsis for "Criminal Minds" season 12, episode 2 reveals that J.J. will arrive home shaken after a case hit a little too close to home.  Breaking down, she tells her husband about the abduction of two children.

From the trailer for the episode, titled "Sick Day," it looks like J.J.'s life will be laid on the line. Along with Luke Alvez and Emily Prentiss, she will seek to capture a serial killer who is into committing arson. In one of the scenes, she is shown walking towards the direction of a horrific scream but an explosion happens just before she even gets to it. 

Meanwhile, fans were surprised when Thomas Gibson's Aaron "Hotch" Hotchner appeared on the premiere episode of the series. It was previously reported that he had been fired from the series following an on-set altercation with one of the show's producers. While neither the synopsis nor the trailer for episode 2 gives fans any idea of how his character will be written off, the producers of the show confirmed that the upcoming episode will be his last show.

"Criminal Minds" season 12, episode 2 airs on October 5, 9:00 P.M. on CBS.