WARNING: The following contains spoilers for Charmed Season 3, Episode 17, "The Storm Before the Calm," which aired Friday on The CW.
In order to figure out how The Charmed Ones can defeat The Whispering Evil, they travel to the Tomb of Chaos, where they visit Aladria, who lays out two options that they have to defeat the ancient evil hellbent on destroying the world. Since they don't want to release the Perfecti nor kill the evil -- which would, in turn, kill Jordan -- they ask for a third option.
Aladria informs them that the evil is mimic-like. It can remember attacks used against it previously, making it's pointless to fight it with something that's been used against it before. This fact leads Macy to realize she needs her demon powers back, mostly because there's yet to have been a demon within The Charmed Ones, so the evil won't anticipate it, nor recall how to counter it.
In Charmed Season 2, Abby strips Macy of her demon powers. At first, she appears to be doing so to help The Charmed Ones -- as the Power of Three wasn't working quite right with Macy still holding onto her half-demon powers -- but the truth is that she wanted Macy's fire powers for herself. This comes to light for Macy in Season 3, Episode 13, while The Charmed Ones are trying to save Abby from living in the eternal prison of the Tomb of Chaos. At the end of Abby's trial, the demon overlord promises to return Macy's powers.
In Charmed's latest episode, Macy is ready to collect what's rightfully hers. She travels with Abby to her family's home where the Blade of Clarity lives -- a tool that can strip Abby of Macy's power and give Macy her demon fire powers back. And while Abby approaches her sister, Waverly, for help, she declines in fear that Francesca will harm her daughter.
Abby and Macy travel to Abby's childhood home in Sussex without her. There, Abby quickly finds the safe, but it's blocked to her powers -- charmed against Abby's magic. Macy steps in and rips open the safe, revealing the Blade of Clarity that's inside. Abby takes the blade and attempts to perform the ritual but is immediately shocked by the blade. Moments after, Francesca Jameson appears and offers Macy an ultimatum: Macy can have her powers back if she kills her daughter, Abby. Macy, tired of the self-serving Jameson family at this point, refuses to do so and is translocated by Francesca. While Macy is gone, Waverly confronts her fears about her mother and comes to help Abby.
Thankfully, Macy arrives back in time to save both Abby and Waverly's life from their wrathful mother. Abby then finally returns Macy's demon powers to her. Macy takes her demon powers for a test drive and is relieved to see her abilities returned. Equipped with her regained fire powers, Macy becomes the key ingredient that ultimately saves the world. Well, at least for now, and until The Whispering Evil that The Charmed Ones expel from Jordan's body finds a new host.
Charmed's Season 3 finale, "I Dreamed a Dream," airs on The CW July 23 at 8:00 p.m. ET/PT.