Centennial Charmed

In his twisted attempt to win Phoebe back, Cole casts a spell that alters reality, eliminating Paige and destroying the Power of Three. Paige suddenly finds that her sisters have no knowledge of her existence -- Phoebe is trapped in an unhappy marriage and Piper is a demon-killing vigilante consumed with avenging Prue's death. Paige finally convinces Piper to trust her, and together they help Phoebe vanquish Cole forever.