The Flaming Lips are playing at P3. Paige's latest fling, Trevor, comes in and offers to take Paige to Big Sur for the weekend, but Paige instead breaks it off with him. Piper and Phoebe are watching; it's the third straight guy Paige has dumped. Piper heads home early; she and Leo are interviewing magical nannies tomorrow. Paige comes over with Phoebe; she had a hunch that she and Trevor weren't going to work and wanted to end it before things went too far. Phoebe mentions that Cole has been too quiet lately--a sign he might be up to no good.
Cole is getting drunk in a dive bar when two robbers come in. They shoot up the place, but Cole is unharmed. Cole flings the robbers into the wall; they attempt to flee but Cole kills them with energy balls. Two black-clad beings appear to him and tell him that they've been waiting for this to happen.
Piper is trying to clean up the manor to make a good impression for today's round of interviews. Leo orbs in and tells Paige that the Elders have given her her first charge as a Whitelighter. Leo can't tell Paige much about her charge except that his name is Samuel. The Elders don't know where he is, but think that Paige can find him. Just as Paige is about to head out, Phoebe rushes downstairs--a vigilante killed two robbers in a bar last night, and the vigilante's description fits Cole. Phoebe wants to vanquish him on the spot, but Paige doesn't want to rush into it.
The two beings from the bar fade into Cole's apartment. Cole still refuses to listen to them, but they say that after last night, he has nowhere else to go. They introduce themselves as Avatars, powerful beings who are neither good nor evil. They are about to make a major move, and want Cole to be a part of it. Cole tries to kill them with energy balls, but they don't even scratch the Avatars. After telling Cole that he will eventually join them, they disappear. Phoebe comes in shortly after and confronts Cole about the bar fight. Cole admits killing the robbers, much to Phoebe's dismay. She warns him not to kill again or she will vanquish him.
Paige, accompanied by Leo, is in an alley trying to find her charge. Paige plans to pass herself off as a social worker, but Leo doesn't think she'll need a cover. Paige suddenly feels a magnetic pull; apparently her charge is close by. They reach the back of a bar just as a stone-drunk man is being thrown out. Paige recognizes him as her charge. Leo orbs back to the manor to get ready for the interviews.
Paige helps Samuel back to his place, but Samuel doesn't want anything to do with Paige. Paige gives her phone number to Samuel. Samuel then surprises Paige by revealing that he is a former Whitelighter and is not happy that the Elders tracked him down or that they sent a novice Whitelighter to find him. However, Paige refuses to leave. A Darklighter, Ronan, orbs in and conjures his crossbow, but Paige shoves him out of the way. The Darklighter recovers and gets Samuel in his sights again.
Piper and Leo are interviewing an elf. The interview seems to be going well, but the elf, knowing that Piper is a Charmed One, is concerned she may have to protect the baby from demons. Just as Piper tries to reassure her, Paige orbs Samuel back to the manor and Ronan black-orbs after them. He shoots, wounding Samuel. Piper blows off one of the Darklighter's arms. Ronan black-orbs away. The elf huffily fades out. Piper and Phoebe recognize Samuel; he is Sam Wilder, their mother's Whitelighter and Paige's father.
Phoebe removes the arrow and Leo heals Sam while Paige checks the Book of Shadows. Sam says he became a Whitelighter for a second time (after dying in P3 H2O), but feels he blew it again. He admits that for years, he's felt guilty over having to give Paige up after she was born. Leo urges him not to walk away yet since the Elders sent Paige to help him. Piper isn't happy that Leo knew this all along, but Leo was sworn to secrecy. Sam tries to leave, but Phoebe wants him to reconcile with Paige. Sam is angry that the Elders set him up, but Leo tells him that they had no choice. Once he stopped using his powers, the Elders could no longer sense him, and only a blood relative could find him. Piper also wants Sam to reconcile with Paige, but Sam thinks he's a failure and orbs away. Unknown to everyone, Cole has been listening in the whole time.
Paige comes back down; she couldn't find anything in the Book. Leo says that Ronan is probably a Tracker, a type of Darklighter who goes after fallen Whitelighters. He's much more powerful than typical Darklighters. Piper and Leo want to find Sam, but Paige feels she should go after him since he's her charge. Leo, however, thinks Paige won't be able to track Sam's orbs. He and Piper orb out.
Cole tracks down Ronan and offers an alliance with him to kill the sisters. Ronan is skeptical until Cole heals his arm. Cole wants to kill the sisters first, then go after Sam. Ronan wants Sam first, but Cole thinks that if they kill Paige, it will break Sam's spirit. He waves his hand in front of Ronan's face and grants him more powers.
Sam orbs to his apartment to find Piper and Leo waiting for him. Sam is bitter over having to give up Paige, and thinks he'd have lost her again once she found out she was a Charmed One. Leo and Piper try to encourage him, telling him that it's entirely possible the Elders brought them together so Paige could learn where she came from.
Paige tries to get Phoebe to tell her more about Sam. Phoebe is initially reticent with details, only saying that Paige might learn something from him like how not to judge people as fast as she's judged her recent dates. Paige doesn't see the connection. Phoebe finally tells Paige that Sam is her father. Just then, Sam appears at the manor. Sam regrets having given Paige up. Paige regards Sam as a stranger.
Piper and Leo orb back in. Phoebe compliments them on convincing Sam to come back, but Piper explains that Sam didn't want to come back. Just as Leo and Piper rush in to warn Paige, "Sam" morphs into Cole and Ronan black-orbs in. Piper tries to blow Ronan up, but the blast doesn't even scratch him; Cole made him invincible to witchcraft. Phoebe throws a vanquishing potion at Ronan, but it doesn't work either. Ronan shoots a bolt from his crossbow, which splits in three, and both Leo and Paige are hit. The third arrow flies toward Piper, but a protective shield appears over her stomach and the arrow falls harmlessly to the ground. Ronan black-orbs out and Cole fades out behind him.
Phoebe is very angry at Cole, and is convinced he's turned evil just as she feared. Piper, however, doesn't see the method to Cole's madness. Piper thinks the only way to save both Paige and Leo is to find Sam and have him heal them. They need Paige to locate him; she can't orb but she can still use her sensing powers to find him. Piper goes out after Sam; she realizes that with the baby inside her, she's now invincible.
Ronan tracks down Sam and is about to shoot him, but Cole doesn't allow him to kill Sam. Cole tells Ronan his real intentions: he wants the witches to attack him, and right now he needs Sam alive to heal Paige and Leo. Ronan tires to attack Cole, but Cole kills Ronan with an energy ball and fades away before Piper arrives.
Piper tells Sam he needs to heal Paige and Leo. They orb back to the manor, and then Sam tries to heal Paige. He can't at first. He pities himself. The sisters tell Sam he needs to let go of his pain and anger. Sam tells Paige he's sorry, and feels his powers return. He heals Paige and then Leo.
The sisters prepare three of their strongest vanquishing potions to vanquish Cole. They test them on the letter opener with Cole's blood on it ("A Witch's Tail, Part 1). Paige's potion sizzles, Piper's makes a small explosion and Phoebe's blows a hole in the rug.
Cole is writing a goodbye letter to Phoebe. The Avatars fade in and ask Cole once more to join them, but Cole refuses. The sisters orb to Cole's apartment. Paige throws her potion, and Piper throws hers. However, Phoebe realizes that Cole is attempting suicide by witch. She refuses to vanquish Cole on his terms, but Cole reaches out and draws the potion to him. A massive explosion blows out the sisters to the ground and shatters all of the windows of the apartment, but to everyone's surprise, Cole is unharmed. He realizes that not even the Power of Three can kill him.
Paige and Sam have a long talk in the living room. Sam knows that Paige still hurts from being given up, but Paige is still glad she led a great childhood, and now has a chance to have a new life with Piper and Phoebe.
The elf warned all the other prospective nannies about the goings-on at the manor, and all of them cancelled. Paige wants to call Trevor and take him up on his offer to head to Big Sur. Phoebe is on pins and needles knowing that not even the Power of Three can kill Cole. Cole walks out on his balcony and sullenly looks outside.