Complete story — includes the ending
When Piper's car breaks down, she is attacked by a vicious werewolf-like beast that they later find out is called a Wendigo. Piper is saved by a man named Billy, but she starts to turn into a Wendigo since she was scratched by the one that attacked her. The Wendigo turns out to be FBI agent Ashley Fallon, who had apparently been tracking the beast. Fallon kills Billy and tries to kill Andy, but Prue and Phoebe go after her with a flare gun as fire is the Wendigo's weakness. Piper shows up as well and they nearly accidentally vanquish her instead, but she freezes the flare and Prue sends it into Fallon, killing her and curing Piper.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, Charmed season 1. HTML formatting and reference markers removed. · Content license