From TVGuide.com:

It may have SPOILERS!

TV Guide: Does Booth (David Boreanaz) survive the shooting?
Emily Deschanel: Let’s just say we left Brennan in a crazy place in the last episode. It feels like she’s losing people left and right. She’s in a place where she’s cutting off her emotions.

TV Guide: Do we discover the identity of the Gormogon, the cannibalistic serial killer that’s been taunting the squints all season?
Deschanel: Yes. I get sent a jawbone from the Gormogon. We learn that he — or she — has infiltrated the lab and might have someone on the inside helping. We start suspecting people we’ve worked with a long time.

TV Guide: Is it true Zack (Eric Millegan) is in another explosion?
Deschanel: There’s an explosion and bad injuries happen. There’s so much going on. We can’t talk about 90 percent of it!