Buffy has an encouraging talk with her biology teacher, Dr Gregory, who she now beleives is the only teacher that likes her. Dr Gregory, however, turns up the next day decapitated and hanging in the school canteen.

The substitute teacher arrives and catches the eye of every boy on campus. Miss Natalie French who appears quite normal takes the class and continues the lesson about praying mantises.

Buffy's first suspect is a vampire whose hand has been replaced by a claw. Whilst battling with the creature later in the park he flees and Buffy just able to keep up watches from the other side of the fence as he approaches a victim. The victim turns out to be Miss French who on looking at him causes him to flee.

Giles takes the information that Buffy has gathered about Miss French, such as frightening the Vampire and being able to twist her head all the way around. He calls a fiend from England, dr. Carlyle Ferris, who is an expert in entomology and mythology.

Giles reveals to the gang that Miss French appears to be the same creature that sent Carlyle mad, a "She Mantis".

Miss French has both Xander and Blayne prisoner in the basement of her house after drugging them. They seem doomed to die unless Buffy, Willow and Giles can rescue them.

Using the clawed vampire as a sniffer dog, Buffy, Willow and giles manage to track down the house and using bat sonar Buffy defeats the creature.