A mouthless demon infects Buffy with the ability to hear everyone's thoughts, but what starts out as a useful power soon turns into a curse.
After an encounter with a mouth-less demon, Buffy is infected with the demon's blood and she gains the ability to hear people's thoughts. At first her newfound ability is useful for cheating on schoolwork and eavesdropping on the thoughts of those around her, but when the voices continue to flood her mind, she realizes that she cannot control the power. Amid the chaos, Buffy hears a killer planning a mass murder at the school. Now she must keep herself from going mad long enough to prevent a catastrophe.
- On patrol, Buffy runs into two demons that she fights and then kills one of them. While the other escapes, the blood from the demon she killed mixes with a cut on her palm she received while fighting it. The next day at the library, Buffy finds that they're making very little progress with the Mayor and stopping the ascension. Willow asks Buffy if she's talked to Angel and then suggests that Buffy straight out ask him what happened with Faith. Percy checks in with Willow to reschedule their study session and then she talks to Buffy about the basketball game after school which everyone except Buffy is going to.
Buffy goes to Giles after she finds that her hand is itching where she was cut and that, because she came in contact with the blood of one of the demons, she may be infected with an aspect of the demon. Xander and Oz watch the cheerleaders at the pep rally and Xander reveals that he still has a thing for Cordy when he witnesses Wesley looking at Cordelia. Buffy is constantly worried as she waits to find out what aspect of the demon she'll be getting; Willow horrifies her, wondering if the demon was a male. She talks to Angel about it that night and he tells her he'd love her no matter what she looked like.
The next day, as she's walking through the halls, Buffy finds out that she can hear the thoughts of others. She talks to Giles about it, and he goes right to work researching it while Buffy decides to put her new ability to work. In class, she listens to the thoughts of her teacher and classmates and answers the questions asked. Buffy also hears the thoughts of Freddy Iverson, who writes editorials for the school newspaper who has a seriously negative opinion about everything at Sunnydale.
That night, Buffy goes to the mansion to use her mind-reading abilities to check up on Angel and find out the truth about what happened with Faith. He figures out what she's trying to do, and he tells she can't read his mind because he's a vampire. He reveals to her that what happened with Faith meant nothing and that in 243 years, he's loved only Buffy.
At the library, Buffy tells her friends about her ability to read minds. Xander constantly thinks about sex, Cordelia says almost exactly what she thinks, Oz thinks extremely deep thoughts, Willow thinks about how she's left out of things, and Wesley thinks about Cordelia.
In the lunchroom, Buffy hears someone think, "By this time tomorrow, I'll kill you all," and then the voices get to be too much and Buffy passes out. When she regains consciousness, she tells everyone to get organized and find out who the potential killer is. Buffy goes home to rest but before she leaves, she overhears Giles's thoughts that she'll go insane if the telepathy continues. He and Wesley found that it happened before, but the person is in total isolation because they can't stop the power. Buffy's mom is nervous around her and doesn't want to stay in the same room with Buffy for very long. Finally, Buffy reads her mind and finds out that she had sex with Giles, twice, on the hood of a police car. Willow and everyone go around interviewing students and faculty that were in the Cafeteria to see if they're potential killers.
Giles and Wesley have found a possible solution to curing Buffy, but it requires the heart of the second demon. Angel hunts down the demon and the next morning brings the heart to the Summers' home in a glass mixed with other ingredients. He forces Buffy to drink it and then her body goes into convulsions. Willow and the rest of the Scooby Gang were able to locate all the students on the list except Freddy Iverson and they all go looking for him.
Back at home, Buffy wakes up and is no longer able to hear thoughts. The gang finally corners Freddy in his office and find out that he's not the potential killer. Buffy shows up just as they find a letter from Jonathan apologizing for his upcoming actions of death on Freddy's desk. The gang splits up to find Jonathan while he is up in the clock tower, assembling a rifle. Buffy spots him from below and puts her Slayer strengths to work as she flies up the stairs, onto the roof, and into the tower. Buffy talks to him and tells him that the reason why everyone ignores him is because they all have their own problems that actually matter more to them than his do. She takes the rifle from him and then finds out that he was really going to commit suicide.
Xander checks the kitchen and stumbles upon the overweight lunch lady putting rat poison into the food. She comes out and tries to kill Xander with a cleaver, but Buffy stops her. The lunchlady likened the students to "vermin" always eating and never stopping. Buffy decides that the lunchlady has lost her mind and knocks her unconscious. Giles and Buffy recap what happened as they walk around the school grounds. Giles asks her if she's up for some training, and Buffy says she is if he isn't too busy sleeping with her mother, causing Giles to walk straight into a tree.