Interpreting dreams is a tricky thing. In "Chuck Versus the Tooth", Chuck suffers through several dreams (or nightmares) that present some interesting conundrums and set the stage for the last three episodes of the season.

While watching television, Chuck says he loves Sarah, but she doesn't say it back. Eventually, Chuck falls asleep prompting Dream #1: Sarah says I love you, Beethoven's "Ode to Joy" plays in the background, Beckman crashes cymbals together, Shaw's at the door with Zamibian take-out, and Chuck shoots Shaw repeatedly until he falls into the courtyard fountain.

Chuck interprets the dream as the death of the Zamibian President at the hands of the Ring later that night at the Beethoven concert. Everyone's angry because there isn't any real evidence that this will happen. Because his dreams are getting in the way of his work (and their sleep), the General assigns Chuck to see a CIA therapist.

Chuck's therapist, Dr. Dreyfus (guest star Christopher Lloyd), asks if he wants to talk about his father. Chuck's reluctant to talk, but they eventually discuss his dreams as a product of his subconscious interacting with the Intersect. The doctor is knowledgeable about the Intersect's side effects, namely its potential to overwhelm Chuck's mind. Chuck assures him that he's not insane and insists he's right about his claims, but the doctor removes him from field duty.

Chuck doesn't want to freak Sarah out so he doesn't tell her that anything's wrong. Instead, he enlists Morgan's help. With tickets to the LA City Symphony and two tuxedos, they're set to go.

At the concert, they spot Kuti in the president's box. Unfortunately, it seems the music is putting Chuck to sleep prompting Dream #2: Chuck's onstage, Shaw's in the audience saying "you shot me, Chuck", and Shaw tells him that the dream is about a scientist, Dr. Kowambe, who Chuck sees with a blade to the President's neck.

Chuck's startled awake, and he spots the guy who's going to kill Kuti in the box with him. He resolves to get up there to protect the President.

Just then, Casey and Sarah enter to diffuse the situation. Casey deals with Morgan as Sarah follows Chuck up to the box. Chuck frisks Dr. Kowambe which shocks the President, but Chuck flashes on Kowambe's tooth (that supposedly contains Ring intelligence) which causes him to punch the doctor. The tooth flies out, and Kuti orders Chuck to be arrested.

Chuck's taken to a psychiatric facility where Dr. Dreyfus reveals to him that everyone there used to be a spy. Wow, that's not at all comforting.

Later, Casey and Sarah visit. Chuck's still sure that he's right about Kowambe, and he wants to convince Sarah, too. He reaches into his mouth, pulls out a tooth, and then slips it to Sarah. He maintains that the truth is in the tooth and asks her not to give up on him.

However, in her analysis, she discovers that it's only a human tooth. Sarah tells Chuck the news, and he thanks her for trying.

Back at the psychiatric facility, there are some unwelcome guests, namely Kowambe and his goons. He gets Chuck alone in an exam room and asks why Chuck took his tooth... the wrong tooth. So Chuck was right! But now Kowambe wants to know how he got his information. He injects Chuck with a truth serum that causes Chuck to get woozy and renders his flashing skills useless. He falls to the ground as he sees Sarah and Casey take down Kowambe and his men.

Back at Castle, the General apologizes to Chuck. He was right about Kowambe, but Chuck's more curious about his own health.

In Dr. Dreyfus' office, the Doc (your requisite Back to the Future reference) clears him for duty. But the doctor cautions that his dreams are proof of the stress the Intersect puts on his brain. He believes the stress will ultimately lead to mental deterioration, and it's something he should discuss with Sarah -- which he doesn't end up doing because she interrupts Chuck by finally saying I love you.

Finally, Dream #3: Chuck's in a hospital bed, and Shaw's standing above him, revealing that he isn't bleeding anymore. Chuck asks what that means, and Shaw answers that he's still alive!