Piper sits in her bedroom, crying into her hands. A knock is on the door. She sees a picture of her, Prue, and Phoebe in front of the manor. A knock is on the door and Piper tells the person to come in. Prue opens the door. Se walks in and tells her that Leo said the Elders are sorry for their loss and the charmed ones. Piper tells her to tell Leo to tell the Elders that they can screw themselves and that no sorry can bring back Phoebe. Prue walks over to her, sits next to her, and hugs her as they cry on each other's shoulders.
In the attic, the Book of Shadows' split triquetra glows red and opens, turning the pages. It stops on the To Call a Lost Witch page.
The following morning, at South Bay Social Services, assistant Paige Matthews is at work when a candle at her desk mysteriously blows out. Suddenly, lights swirl around her head, and a newspaper drops out of thin air behind her. It prominently bears Phoebe's obituary, and Paige feels the need to leave. At the manor, Victor, Leo, and Darryl meet the surviving sisters. Victor wonders where Cole is and why he couldn't save Phoebe. Leo is sorry that he was unable to save Phoebe, and Prue feels guilty that he saved her and Piper instead. She believes that had she not exposed magic to the world, Phoebe would be alive. In the Underworld, the Source consults his Oracle, and here he reveals that Leo had escaped, but he made Cole watch him kill Phoebe. He also reveals that Cole escaped and is missing. The Oracle tells the Source of another possible Charmed One.
The funeral is done, and Paige is among the attendees. Paige approaches Prue, perhaps not knowing why. While Darryl's partner, Inspector Cortez, arrives to inform the Halliwells he's on the case, Piper, frustrated, tries to summon Phoebe with a spell, but her spell summons Grams instead. Grams says she couldn't come earlier because she and Patty were with Phoebe. Grams tells Piper that she can't see Phoebe just yet, that she must let go. The Source again consults the Oracle, who shows him Paige dancing at P3. It turns out Paige has been coming to P3 for the last year. She tells her story to her date, Shane: that she was adopted, that her adoptive parents had died, and she is looking for her birth family. She thinks she might be related to the Halliwells, though she is uncertain about it and unwilling to approach them. Both leave the table, and it turns out that Paige has idly drawn a triquetra on a napkin.
Sure enough, Paige and Shane come onto the rooftop and embrace. Shax appears and blasts Shane, and then turns on Paige and, Paige briefly orbs, dodging Shax's attack. Paige leaves, with Shax following behind. Prue is driving when she sees Paige running out of a building. She stops her car and gets out of the car. Paige raches her car and begins to get unlock her car and Prue runs up to her, scaring her. Prue asks her what is wrong. Shax appears behind them. Prue tells Paige to run away and as soon as she does, Shax attacks Prue and leaves. Right after, Paige comes back and sees Prue lying on the ground bleeding. She nervously calls 911.
Prue recovers in the hospital with only a concussion; However, Shane is in a coma. Piper and Leo meet with her. Piper asks her who attacked her and Prue tells her it was Shax and she tried to protect an innocent. Piper begins to be angry with Prue. Paige meets with Prue, Piper, and Leo. Paige thanks Prue for saving her. Paige tells Piper that she loves going to P3, to which Piper says thank you. Prue tells Piper that Paige reminds her of Phoebe. Inspector Cortez meets and talks to them, telling them they're lucky to be alive because their attacker was the same one that killed Phoebe and Dr. Griffiths. Paige begins anew to suspect her connection to the Halliwells.
Later on, Leo reports that the Elders know nothing of Paige, and can't explain how she can orb. A loud falling sound is heard from upstairs and Prue, Piper, and Leo go to the attic. They find a demon in a crystal cage to which Prue tells them that she set up so a demon couldn't steal the Book. The demon sarcastically tells them that he's glad their sisters' are dead. They blackmail the demon into giving up the Source's plans. He tells them the Source thinks Paige is not only a witch, but related to Prue, Piper and Phoebe--a fourth Charmed One. He thought the Power of Three had died with Prue--hence his decision to send Shax after Paige. Piper again summons a puzzled Grams. Grams says she is sworn to secrecy, and won't answer, but Patty then appears, and explains Paige's origin. Paige is her youngest daughter, the product of the relationship between Patty and Victor; However, she is also part whitelighter due to Patty having whitelighter Sam's powers also. Although Patty had initially wanted to keep her, she and Grams ultimately decided to give her up out of fear that the Elders would strip Prue, Piper and Phoebe's powers as punishment. If they can bring Paige to the Manor, then the Charmed Ones might be reconstituted.
Cortez enters the attic with Darryl behind him. He finds Grams and Patty in ghost form, and accuses Prue and Piper of practicing evil magic as well as killing Phoebe and the doctor. After hearing him threaten to put them under constant surveillance, Darryl hits Cortez over the head and knocks him out. Prue urges Darryl to leave, and Leo opts to orb Cortez to his house and erase his memories of the Halliwells.
After Grams and Patty leave, Prue and Piper come downstairs and find Paige in the manor. Piper shakes Paige's hand. The chandelier shimmers, and bathes the three sisters in a bright light. Shax barges through the door and knocks the sisters down. Leo orbs in and jumps on Shax's back. Prue, Piper, and Paige run to the attic. Shax barges into the attic and the three sisters recite the spell from the Book of Shadows, vanquishing Shax at last. Paige, however, is frightened and runs from the manor.