Brace yourself, Bones fans: Booth and Brennan are ending their relationship — or at least one of their relationships.

Let me explain: In the first half of the upcoming midseason finale (Thursday, Dec. 10, 8/7c, Fox), Booth (David Boreanaz) and Brennan (Emily Deschanel) will once again go undercover as Buck and Wanda to solve a case at an Old West-themed shooting competition. But Buck and Wanda won't be working as a couple.

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"Booth is much more into the idea of going undercover than Brennan is," executive producer Michael Peterson tells TVGuide.com. "She's like, 'This is a waste of time. You just want to wear a silly cowboy hat and guns.' She doesn't believe that it's actually necessary for the case, so she doesn't join him initially. She comes in later, but it changes the dynamic. Every other time they're basically a couple going undercover, and this time they're getting to play strangers to one another. They've been married for so long and to get to see each other in a different dynamic was a fun opportunity we wanted to take."

Now that you've hopefully calmed down, you should know, however, that "fun" isn't in the cards for other couples on the show. I hear that in that same episode, Cam (Tamara Taylor)'s involvement with Sebastian Kohl (guest star Gil Darnell) takes an interesting turn that makes things more than a little awkward when Arastoo (Pej Vahdat) comes back. Plus: Angela (Michaela Conlin) and Hodgins (TJ Thyne)'s marriage will be seriously tested by another twist.

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