Prue is at the lake where her mother drowned when she sees a demon take down a boater. A man tries to protect Prue and keep her from getting taken by the demon as well. Prue and her sisters realize that this is what killed their mother, and the man at the lake was their mother's old white lighter, Sam, now mortal. The sisters decide to finish what their mother started, but as the story unravels, it turns out that Sam and their mother were in love, and their mother froze Sam when he came to protect her at the lake, so she was distracted and taken by the demon, and Sam didn't even get to see it happen and blames himself. Phoebe has to look back into the past and relive their mother's death so that Prue will know that she was trying to electrocute the water demon to vanquish it. Prue and Sam go to face their demons, and Sam dies after absorbing the water demon and then electrocuting himself. Jack Sheridan comes to work at Buckland's, and covers for Prue while she is out fighting demons. After seeing the consequences of another white lighter in love with the witch he was supposed to protect, Leo realizes he and Piper can't work together anymore. Piper tries to move forward with her relationship with Dan.