Blood and loyalty prevail, however, and soon Paige takes over Phoebe's old role as screw-up rookie, mangling potions and causing havoc (such as switching bodies with Phoebe at an inopportune time). But her strong survival sense, compassion, and ability to read people (she's studying to become a social worker) add a powerful new weapon to the Halliwell arsenal. Meanwhile, several key storylines from the third season carry over to this new year, notably the running drama concerning demon-with-a-soul Cole (Julian McMahon) and his ongoing battle to stay free of hell's wrath while maintaining dark powers. His romance with Phoebe leads them to become ruler and queen of the Underworld, where Phoebe's loyalty is tested and a demonic baby enters the picture. Piper and her husband, Whitelighter Leo (Brian Krause), deal with sorrow over Prue and frustration over not being able to have a child, and the sisters' police ally, Inspector Morris (Dorian Gregory), has to contend with an out-of-control boss bent on charging the Halliwells with a crime. All that and a witch-hunter and appearance by the angel of destiny, who offers to relieve the witches of their magical burden. The most impressive aspect of the fourth season is the way Doherty's loss isn't treated as a mere vacuum to be filled with a new body, but is taken as an opportunity to reinvent the show in several crucial ways. --Tom Keogh