The Charmed ones come up against a powerful ancient warlock called Aames. With the aid of another "Whitelighter" called Natalie the Charmed Ones and Leo go after Aames.
When Piper and Leo begin to have marital problems,Piper casts a spell to allow them to literally see their past together.The spell goes awry when Phoebe and Paige are sent back in time to relive Piper's memories.