Credit: Greg Gayne/FOX Photo: Bones Breaks Booth's Heart in Season 5, Episode 16: "The Parts in the Sum of the Whole"
Bones is known to throw us off the case a time or two, which is part of what makes it really fun. Just when we think the suspect is Mr. X, it turns out to be Mrs. Y. Wowsa! Didn't see that coming! But the writers generally don't throw a huge twist into the overall arc of the show. (Generally being the key word here.) When they do, it hits you right between the eyes, and even leaves you angry and disturbed. Here are five of the biggest plot twists so far on Bones.

5. Booth confesses his feelings
He loves her! Booth says he loves Brennan and has since the beginning. Plot twist, you ask? Yes, because on a show like this you never expect one of the romantic leads to actually come out and do the sensible thing and just say what he feels. What made this moment more of a plot twist was that Brennan basically said no thanks. Doh!

4. Brennan helps her dad get out of jail
If she just relied on her logic alone, as she so often does, Bones would have worked to convict her father. Instead, her heart won out, and she did just the opposite. Is she learning to deal with her feelings? Granted, Booth basically planted the idea in her head to give the jury something to doubt, but she's the one who went ahead and did it. Who saw that coming?

3. Booth comes back with a girlfriend
Booth has poured his heart out to Bones and been rebuffed, and she's beginning to realize she made a mistake. Right before leaving for their new jobs abroad, they agree to meet back in D.C. in a year, and it's all terribly romantic. But just when you think they're finally going to get together, Booth returns from Afghanistan with a blond, beautiful girlfriend. What's worse? It's hard to hate her.

2. Brennan finds the bones of her mother
Finding her mother's bones was a huge shock for Brennan, especially since the facts about how she died don't coincide with what Brennan always believed. You know how Brennan is with those facts. Good thing her pals in the lab were able to talk her out of her denial regarding the dates surrounding her mother's disappearance.

1. Zack confesses to… murder?
Sweet, adorable, by-the-rules Zack is giving aid to a cannibalistic serial killer? Even more shocking, he really didn't kill the lobbyist! But he wasn't entirely innocent, either: He admitted later to Sweets that he didn't do the actual killing, but he'll just stay in the mental hospital for now, thank you. This plot twist still boggles the mind.