"[S2E8] P3 H2O " refers to the eighth episode of the second season of the supernatural drama series Charmed , which originally aired on December 9, 1999. This pivotal episode explores the sisters' past, specifically the mystery surrounding their mother's death. The title plays on the chemical formula for water ( H2Ocap H sub 2 cap O
) and the sisters' club and collective identity as the "Power of Three" (P3). [S2E8] P3 H2O
: The sisters discover that their mother had a secret, forbidden romantic relationship with her Whitelighter, Sam Wilder . This relationship mirrors the internal conflict Piper feels regarding her love for Leo. "[S2E8] P3 H2O " refers to the eighth
: Prue Halliwell must overcome her lifelong trauma and fear of drowning to vanquish the demon using her telekinesis and electricity. : The sisters discover that their mother had
: The sisters return to Camp Skylark, the site where their mother, Patty Halliwell, drowned 20 years earlier. They must confront and destroy the Water Demon responsible for her death before it kills again.