Charmed narrative follows the four Halliwell sisters, Prue, Piper, Phoebe and, later, Paige, the culmination of the long Warren line of powerful, good witches. The sisters, despite being perceived as normal by the non-supernatural community, are known as The Charmed Ones, whose prophesised destiny is to battle against evil beings, such as demons and warlocks, in order to protect innocent lives from being endangered. Each sister possesses unique magical powers that grow and evolve, whilst they also attempt to hold normal working lives in San Francisco. Keeping their paranormal identities separate and secret from their ordinary lives forms part of the series' tension and challenges, with the exposure of magic having far-reaching consequences on relationships and has resulted in a number of police and FBI investigations throughout Charmed .