Casey and Sarah are visiting Chuck in the hospital. He tells them he needs them to analyze some evidence for him, and then coughs up a tooth into Sarah's hand. Even she's obviously beginning to think he's a nutjob. Chuck tells them it's not a real tooth, but has information in it they need to analyze. He says the tooth is the key. "The truth is in the tooth." Casey's like, "Uh, yeah, okay, you get some rest there, buddy." Chuck tells Sarah not to give up on him, and she says she won't. They kiss and she watches him go sadly. But, back at Castle, she runs the tests. Casey's there, too, and they both want him to be right, but Casey's more realistic about it. And ... the analysis says it's a 100 percent human tooth. Sarah sadly says Chuck was wrong, and Casey tells her he's sorry.
Buy More. Morgan finds Casey and asks him where Chuck is. He begs a little, and Casey tells him he's locked down in a psychiatric facility because the Intersect's giving him a bit of a hard time. Morgan thinks it's crazy. Anna comes in again to try to talk to Morgan, but he wants to follow Casey and talk more, so he tells her he doesn't have time. She still looks good, though. She's left standing there, muttering, "Dissed twice by Morgan Grimes? I can't believe this." Chuck's playing games with the other nuts at the hospital when Sarah calls to tell him she ran every test possible, and it was just a tooth. She tells him to stay positive, that everything's going to be okay. He tells her thanks for trying, and sadly hangs up. Then, so the audience doesn't doubt Chuck for long, Kowambe and his men show up at the hospital and ask to see Charles Bartowski.
After commercials, Kowambe tranqs the guard and receptionist so he and his men can just break in to this CIA facility. It's really that easy (let alone them even knowing Chuck's name and where he is). Meanwhile, Sarah shows up at Doc's and tells him there has to be more to what's going on with Chuck, because he's not like other people; he's incredibly special. Doc answers her with questions, all "Why? Because you care about him?" and "Especially to you, I gather?" She wants to go to the hospital tonight and talk to Chuck. She tells him she loves Chuck, and he wonders if she's ever told Chuck that. She begs him to let her go, and Doc says he's not the only one. He opens his door farther to reveal Casey's there, too. They smile at each other.