Initially, Buffy finds this power very fun. She can hear people complimenting her, and she can read teachers' minds and give them the answers they want in class. But after this initial fun the people who know about it like Xander, Willow, Oz, ect., don't want to be around her anymore because thoughts are too private or can be embarassing, especially if you're Xander and you don't want Buffy to know you think about sex all the time.
Buffy goes over to Angel's house where she tries to read his thoughts on Faith. Well, it ends up that she can't read him for some reason (Angel gives a short explanation but it was too mumbled to hear, something about a vampire's brain being a mirror and it just reflects Buffy). Anyway, Angel gives Buffy reassurances that he's known a lot of "bad" girls in his partying vampire youth but has only loved Buffy, so she shouldn't worry about him.
Later, Buffy ends up in the lunchroom which was a HUGE mistake because that's tons of people having tons of thoughts crushing into Buffy's mind. She is overpowered by the thoughts but does hear one chilling thought that scares her. Someone is going to kill all the people in the lunchroom the next afternoon. After this Buffy is so overwhelmed she faints and is woken up by the Scooby Gang. Giles takes Buffy home to rest up and the others go on a search for the person who is plotting to kill the students.
At home Buffy ends up reading her mother's thoughts and has a shocking revelation. It is finally confirmed that Joyce and Giles had sex on the police officer's car in "Band Candy". This totally disgusts Buffy and embarasses Joyce.
Meanwhile, Giles and Wesley discover that the other person who accidentally acquired telepathy via a demon went insane and is now in isolation. Xander, Willow, and Oz comb the school and ask questions under the guise that these are personality questions that will be put in the yearbook when in reality they're questionaires Willow got off the FBI's database on serial killers, hoping that someone's answer to a question would tip them off to someone's emotional instability. They finally all corner a suspicious guy who is the editorialist for the school newspaper. It ends up that the guy was hiding out because he was afraid the gang would beat him because he gave Oz's band a bad review, not because he's a psycho killer.
Angel locates the other demon and takes out its heart. Giles and Wesley mix a potion with the heart, Buffy drinks it, and voila, she can't read minds anymore!
In the office of the editorialist Buffy finds the gang and they see a little message to the student body from Jonathan, the nerd, who hopes people will forgive him for what he plans to do. Buffy thinks she's found her mass murderer so everyone break up in search of Jonathan. Buffy finally sees him over the courtyard in a little tower putting together a rifle. She does some amazing running and jumping and manages to get up to the window there. Buffy lectures Jonathan that killing people is not the answer although she understands how he feels about feeling like he doesn't belong. Jonathan is momentarily confused because he didn't want to hurt anyone except himself, he was planning on commiting suicide (although I find if hard to picture someone shooting themselves with a rifle, it's too long). This shocks Buffy because this means she still has to find the planner.
Xander gets hungry from running around school so he stops in the school's kitchen to grab some fruit he walks in just as the cafeteria lady is pouring rat poison into the day's food. He runs out of the kitchen screaming with the lady on his tail with a cleaver in hand. However, Buffy beats her up and everyone is saved.
We see Buffy and Giles walking across campus discussing the outcome of this experience. Jonathan has been suspended and Buffy sympathizes with him but when Giles suggests she ask Jonathan to the prom she gags. Giles makes a crack about how she hasn't lost her shallowness in this whole mind-reading escapade. Buffy counters with that she hopes Giles won't be too busy having sex with her mother to train that afternoon. Giles walks into a tree.