As Barney (Scott Baio) is causing mayhem with his telekinesis at the prom (a la Carrie, but in a lighthearted, ripping-off-peoples-clothes-for-no-good-reason kind of way), he decides to unravel a fire hose to (apparently) hose down the crowd. However, Bernadette (Felice Schachter) distracts him as he is bringing the hose out, and as a result, the nozzle flies over and hits him in the head and knocks him out.
When he comes to, he finds Bernadette and Peyton (Willie Aames) checking on him. He then attempts to move something telekinetically, but discovers that he is unable to. Bernadette reasons that the blow to his head and subsequent loss of consciousness must have shifted his brain back to normal and caused his powers to vanish. Peyton soon leaves to chase after some half-naked gals.
As Barney and Bernadette are leaving the school, Barney initially reveals in secret that he still has his powers, and no doubt hid them from Peyton so he wouldn’t be able to take advantage of them for any future schemes he might have in mind. Once outside, Barney offers Bernadette a ride home, and then he uses his telekinesis to fly him and the surprised Bernadette off into the night.
Thanks Tornado Dragon!