Thomas Gibson, Criminal Minds

Criminal Minds marks its 100th episode by circling back to the beginning and addressing issues raised then, as well as bracing for a future with a "new reality" — and "new family."

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"There's a question raised in the pilot episode of whether you can spend your time hunting monsters and not become a monster," executive producer Ed Bernero tells TVGuide.com. "We wanted to revisit that question 100 episodes later and see if the answer changed. Hotch [Thomas Gibson] does something that makes you wonder what's happened to everybody [since the start]."

Bernero promises two deaths by the end of Wednesday's episode. "We're going to definitely lose somebody very important to all of us in this episode, and it's going to change our team and a member of our team going forward. We're going to have to watch these characters come to grips with a new reality. There's a funeral in the 101st episode. The funeral is the beginning of the new reality, the new family of the show."

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Bernero says Hotch will get a new appreciation for his teammates, all of whom band together to cope. "They all learn to support each other in a different way," he says. "We've all seen them be supportive of each other through work, through their lives at work. But this is sort of a new way of supporting each other, which each of them comes to a little bit differently."

The 100th episode also brings back familiar faces. "Everybody you've seen through the 100 episodes who isn't a bad guy is back," Bernero says. "Will (Josh Stewart) and the baby are with J.J. (A.J. Cook) and it's through the baby that she has the realization of how to get the next piece in finding the Reaper. Kevin (Nicholas Brendon) helps Garcia (Kirsten Vangsness) narrow down where he might be. Tina, who's been an evidence technician for us a few times, processes some evidence and Anderson our ghost guy  helps us move forward as well. Everybody is back for a little cameo."

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All that leads to the BAU to stop the only killer they've not been able to catch: The Reaper (C. Thomas Howell). "They realize he's not going to go away and he's going to keep messing with them," Bernero says. "Finally, they go back to what they do, which is [building] the profile, to find out where it is that he's ultimately going."

So once the Reaper is brought down, will Hotch reclaim his role as unit chief from Morgan (Shemar Moore)?

"Hotch has a decision to make — he is offered early retirement," Bernero says. "There will be a few-episode arc about what exactly Hotch is going to do and what Morgan is going to do. Do you go back to the old team concept? I think they all come to a different paradigm in how the team operates. It's much more a shared responsibility than it was before."

Are you excited for the show's 100th episode?