Paige joins Phoebe at the scene of a fire, which they have been called to by Agent Brody. Brody has been investigating several incidents in which someone survives dire peril, only to be killed shortly after, and thinks these incidents might be connected to the worrisome mysterious "new power."
A man jumps from a burning building and somehow miraculously grabs a fire escape, sliding rapidly down two floors and landing without injuries. Agent Brody radios to a helicopter flying overhead to keep their surveillance camera on him. As the crowd, vehicles and firefighters fill the backdrop, the camera pans over one face watching the survivor.
Shortly after, the whole street scene freezes as a guardian angel appears behind the survivor. With his power of suggestion, he tells the man not to cross the road, because of the truck arriving. At this point, the man who was hidden in the crowd, draws the guardian angel into his amulet, then departs at super speed. When the scene and all witnesses, including Brody, Paige and Phoebe unfreeze, the survivor continues his step off the curb and into a crosswalk directly in front of a large fast moving truck, which hits and kills him.
Soon after, in the Underworld, Sarpedon summons another demon, his mentor Aku, and challenges him to a fight. Aku quickly wounds Sarpedon while barely raising a sweat, but nonetheless, condescendingly notes with a hint of approval that Sarpendon's fighting has improved. Both demons can move at super speed and so are individually very powerful. Sarpedon says he needs to collect more guardians to protect him from the new power. Meanwhile, Piper suggests to Phoebe that Leo should take a vision quest. Phoebe thinks this idea is risky, but begins to prepare a potion.
Paige goes to Brody where he shows her a photo of the survivor, taken from the helicopter; it shows a bright light where the guardian angel had been. Brody guesses that the bright figure is a guardian of some kind and that he himself has powerful guardians.
The floating heads taunt Leo atop the Golden Gate Bridge. Leo orbs away and the floating heads turn into Avatars. They want Leo to join them and make plans to persuade him. Piper and Phoebe call for Leo, but he doesn't want to be around the manor. The sisters persuade him to take his vision quest.
Paige orbs Brody into a burning building and then she orbs out at his request; he asks his guardian which way to go and jumps. He falls onto an awning and has only minor injuries. Paige casts a spell and the scene slows; Brody's guardian angel appears, and so does Sarpedon, who takes Paige's guardian instead of Brody's. Paige quickly becomes very accident-prone.
Leo takes Phoebe's potion and sees the scene of his death on Guadalcanal. He meets his spirit guide, Chris. Chris tells Leo that he is Leo's root pain, killed by all that Leo had thought was good. Leo takes Chris's hand and Chris shows him the key scenes in his life: his union with Piper, the birth of Wyatt, and the birth of Chris himself. Chris tells Leo that he is supposed to be about good, that he needs to believe in good again.
Paige and Brody find the Celerity Demon in the Book of Shadows. He has a two-bladed knife and the ability to slow time.
Sarpedon fights Aku again and wounds him this time. He is after the other two Charmed Ones' guardians; Aku thinks that even this might not be enough to fight the Avatars.
Leo awakens for a moment, but a floating head, unseen by the sisters, possesses him. Leo has another vision of tombstones bearing family members' names and sees one of the Avatars. The Avatar tells Leo that the clash of good and evil is vain and that it will lead in time to nothingness, a void.
Sarpedon bursts in and attacks, but Leo, Piper and Phoebe are protected by a crystal cage. Paige orbs to the attic and throws a potion, but it bounces off unbroken. Brody comes up after her; Sarpedon seizes him and bursts away.
Paige scries and finds Sarpedon and orbs to his lair over Phoebe and Piper's objections. Piper and Phoebe leave the attic to make a vanquishing potion, with Leo still having his vision, but Sarpedon bursts in and stabs Phoebe. She grabs his amulet before falling down dead. Piper blasts Sarpedon but the explosion drives his knife into her; she dies as well. Leo emerges from his trance and the Avatar is still with him. Leo cannot heal Phoebe and Piper as an Elder, but he agrees to become an Avatar and thus, is able to revive his wife and his sister-in-law. Leo has apparently improved, but does not admit to having become an Avatar.
- Balance Between Good and Evil: The Avatar argument is that good and evil can never overcome each other and will simply fight until nothing is left.
- Leo himself noted at the start of Season 4 that Elders don't have the power to heal the dead. So, when he sees that Piper and Phoebe were killed during the attack, Leo agrees to become an Avatar and obtain the needed power to revive them.
- To show that the pain and sacrifice has been for good, Leo's vision quest shows the site of his original death, a night with Piper, and the births of Wyatt and Chris.
- Dream Walker: The Avatars appear to be this, as one of them enters Leo's vision and changes it into a sales pitch to join them.
- Helpful Hallucination: The Chris Leo sees is not actually Chris, just a manifestation of Leo's spirit guide/his subconciousness. He leads Leo onto a vision that actually seems to help Leo come to terms with everything that's happened, until the Avatars hijack said vision at least.
- Little "No": Piper when a stabbed Phoebe passes out.
- My Greatest Failure: Leo's spirit guide manifests itself as Chris.Chris: I died in your arms, Dad, killed by everything that you thought was good. I'm your root pain, okay? And I'm gonna be sticking with you until you're ready to let me go.