The season four premiere "Charmed Again" reveals Leo arrived in time to heal Piper, but Prue died of her injuries, reflecting Doherty's departure from the series. Leo assisted Phoebe to escape the Underworld, absconding on the Source's deal. With Prue dead, the sisters are no longer the Charmed Ones, and Cole does what he can to assist Phoebe and Piper from Shax's continued attacks. Piper and Phoebe regain their full abilities—becoming Charmed Ones once again—when they discover their younger half-sister, Paige Matthews (Rose McGowan), alongside whom they finally destroy Shax.