Leo, Paige, and Phoebe go to Alexi's lair per advice from Cole. Unfortunately, they find her dead with one of Rennek's arrows sticking out of her chest. Alexi appears to the group from inside of her mirror, having infused a piece of herself within the mirror in order to give the Charmed Ones information on how to deal with Rennek. Alexi tells Leo that the key to the future lies in his past.
Meanwhile, back in San Francisco, Prue is target practicing with a magical crossbow acquired from Glynnis. Piper arrives and demands that Prue practice on her while simultaneously trying to motivate her to fight in the battle against Rennek, reminding her of the person she is and how she's affected her life.
In a flashback to the '50's, Leo is mourning the death of a charge named Nancy who has just been murdered by Rennek. Leo asks Rennek why he would do this and the Darklighter replies that it's just what he does. Time skips to the '60's where Leo is confronting Rennek once again after he kills a male witch. Rennek once again declares that he's just following the rules and it would be more interesting if Leo fought back. However, Leo declares his stance against violence which continues into another time skip where Leo protects two of his charges. We skip ahead again to Leo being disgusted at Rennek for desecrating people's dead bodies by trying to recreate Michael Jackson's "Thriller" video using real zombies. Rennek then ties to egg Leo on to fight him, telling him that he doesn't seem like the type to "spank him and send him to his room." The next memory shows Rennek disillusioned while murdering another witch, bored with his role in the grand design. He then says that Leo will be his final kill but this time he fights back, wanting to end Rennek's reign of terror once and for all.
Following the battle, we find Gideon and Leo outside of the Manor, Gideon telling him that because he defeated Rennek, the Elders feel he's ready to deal with these difficult charges.
Rennek is watching them in secret, having faked his death, hoping that he would be left alone for good. Alexi then appears to him, telling him that "they" would leave him alone for a while. Rennek tells her that he's played his part and doesn't want to be a pawn in a war he didn't start. Alexi tells him that he has a role to play in the battle and evil finding him again would be inevitable.
Next, we flashback to when Rennek kidnapped Leo and used the Dark Priest to probe Leo's mind for the collected information of the Elders and Avatars hidden in his subconscious. Inside Leo's head, the priest reveals that before the Source's power was divided, before the Charmed Ones were reunited, the magic of the world was in balance. Now that the balance is weakened, it is the perfect time for Rennek to strike. Rennek tells him that he already knew that and wants to know what to do next. The priest informs him that the spell to end the battle requires a powerful artifact from his side of the fight and we see Rennek stealing the Grimoire. The priest tells Rennek to then use that artifact to gain control over a relic of his enemy and we see Rennek casting a spell out of the Grimoire outside of the Manor, gaining control over Leo's Empyreal Sword. The priest then tells Rennek to bring the objects together at the convergence of the dimensions and the battle will be no more.
Back in San Francisco, Piper and Prue are still training. Prue asks Piper what's the point of training if Piper's going to hold back. "It's not about my strength, Prue. It's not the magic or spells. It's about who we are no matter what powers we have. You're good at what you do because you're good. That's what matters," Piper tells her as she freezes her entire body apart from her head. Piper takes this time to tell her that she loves and needs her. The others then return, interrupting their conversation. They tell the two oldest Halliwell sisters what they learned from Alexi; how Rennek divided the magical energy that runs through every living thing. Leo explains that Earth is the juncture point that links the Heavens and the Underworld with the magic that flows through the dimensions and that's why demons always want to take over; if they control the point of convergence, they can control the All. He goes on to say that the Elders protect the Earth to maintain equilibrium but the recent events threw the balance of magic off, citing Prue's return as a factor of that along with Neena dividing the Source's magic and Rennek stealing the Grimoire and the Empyreal Sword. Rennek used the imbalance to divide the dimensions, ending the fight. "Demons can't escape the Underworld. Angels and Elders are trapped in the Upper Regions. The Earth is still connected to the All but it's separate, alone." Leo reveals that Rennek did it by taking control of the point where the dimensions are linked, at the place on Earth where magic was at its strongest before the creation of the higher realm, the Nexus of the All.
Darryl is able to magic a satellite to the location. Phoebe asks why demons don't bother attacking the junction instead of always coming after them. Leo tells her that very few beings know where it is except for Neena who stumbled across it thousands of years ago and apparently him thanks to the knowledge he subconsciously gained. Darryl is unable to find the exact point by allowing them to see anything of it there, but after the sisters use a Power of Three spell (which Prue humorously scoffs at because of the wording), they're able to see the junction and are shocked by how huge it is. Piper determines that they're going to need the help of Prue and everyone else they know.
At Knox Academy, Elise and Tyler tell Phoebe that they demand to be a part of the fight and everyone gets teleported to the location in the desert. Glynnis then gives Leo a replacement sword and declares to be a part of the fight too. Leo then tries to comfort Prue who feels guilty for having a role in Rennek's plan. Paige tells her that she can be glad that her being there might help put an end to it and orbs them to the desert. There, Phoebe is levitating to the highest point of the Nexus, which is a huge dome, and is able to sense the power rising from it. She goes to get a closer look and finds beings coming out of the it.