The third season sees many dramatic changes in the sister;;;s lives. Prue is looking for balance in her life. Piper and Leo;;;s relationship becomes serious. Phoebe starts a new romance with Cole Turner, a half demon sent by The Triad to destroy the sisters. The Charmed Ones begin to discover and understand the hierarchy of the underworld, as they learn of The Triad who are responsible for sending Belthazor and various other demons after them.