We open with Fiona killing the Sarcana, and Harry trying to stop her. Fiona has put a collar around Harry’s neck so she can shock him every time he disobeys. When she injures herself, she forces him to heal her.
A Sarcana member appears and tries to take down Fiona, but her new powers fight against her easily. Fiona claims she’s taking them down because they are just like the Elders—wanting to use her to control magic.
It turns out the Charmed Ones are viewing what happened to the Sarcana through one of the dead girl's eyes from their attic, using Macy’s evil sight. The girls realize Fiona is keeping Harry so he can heal her an keep her safe.
Allister is shown talking to Charity, explains how he wants her to help raise the source of all evil. Allister then decides it’s time for Charity to turn herself in.
Charity brings herself willingly to the Elders, and they bring her to Tartarus. Wearing a magical suit, she blows up her capturers and steps into Tartarus herself.
In the Attic, the girls call for Tessa and explain what happened with Fiona, planning to use her to get Harry back. Tessa tells them to stay away from Fiona while she looks for Harry. The girls hug her in appreciation and put a tracking ring on her when she’s not paying attention.
At the lab, Macy is faced with seeing Galvin again. Macy explains the break up to Parker's mother, and Parkers mom then tells her Parker’s trial has been going well, and she would be happy to help Macy get rid of her dark side. Like she said to Galvin, Macy tells Parker’s mom she wants to keep her demon side—she can control it and use it to her advantage.
Parker and Maggie talk about having sex, but Parker wants to wait until he’s fully human.
Niko shows up while Mel is walking alone. She starts questioning Mel and wants answers. However, Mel is busy trying to track down Tessa, but her compass only leads her to a garbage can, where Tessa has tossed the tracking ring. Niko promises she can help.
It’s time for Parker to fully become human. His mother injects him with a serum. He starts hyperventilating and then burning up. He throws his mother across the lab and she lands unconscious. He tries to wake her but he’s unsuccessful.
Macy comes to the lab and finds Galvin there. She’s worried why she can’t find Dr. Julia.
Niko and Mel meet up at the bar to talk about finding Tessa. Niko has a hit on Tessa’s location, so Mel agrees to bring her along.
On campus, Maggie is walking alone at night and meets up with Mel and Niko. Mel explains Niko is helping her find Tessa, and Maggie tells them she’s off to have human sex with Parker.
When Maggie gets to Parker’s dorm room, no one is home.
Macy is still trying to find Dr. Julia at the lab. Galvin comes back worried Macy is right—something is wrong. Macy goes to check the Dr.’s car and Galvin agrees to help her.
Mel and Niko break into Tessa’s apartment, but Tessa ends up coming home.
Macy and Galvin check out Dr. Julia’s car, and find her unconscious and tied up in the trunk. Galvin tries to call the cop, but Macy thinks it might be demonic and they should wait.
Macy brings the body back to the house and tells Maggie that Dr. Julia is dead. Macy explains that she found a syringe of demonic power on the floor, and Maggie worries that Parker may have been the one to kill her. Macy tells Maggie she has to find Parker, and she will use her evil sight to figure out what really happened.
Mel and Niko hide in a closet while Tessa gets a call from the Elders. she promises to deliver Harry straight back to them. Tessa then gets a hit on where Harry may be. Mel then does Sarcana spell to tie herself to Tessa and follows her as Tessa orbs out.
Tessa finds herself to an underground lair where Fiona is abusing Harry. Fiona explains she wants to destroy magic, and won’t let the Charmed One’s stop her. Harry tries to tell Fiona that the Charmed One’s can help, but Fiona shocks him with his collar and refuses to listen to him. Fiona reveals they are trying to find the origin Dagger.
In the Attic, Macy uses her evil sight to see Dr. Julia’s death. When she looks back, she sees Parker turning evil and Julia collapsing. She then wakes up, after Parker has fled. She then turns back into Parker’s brother, who is the real killer.
Maggie finds Parker and he confesses to killing his mother, not knowing the truth. Maggie becomes scared of Parker, worried about what he is capable of with his demonic nature still intact. Parker leaves upset, but then Maggie is also revealed to actually be Parkers brother.
Fiona is still at the lair with Harry searching coffins for the dagger. Mel shows up and tells Tessa they need to stop her immediately. Tessa wants to go to the Elders but Mel begs her to stay. Niko shows up to help as well.
The sisters try to attack Fiona but are unsuccessful at taking her down. Tessa gets knocked down by Fiona’s bolt of lightning but tells Mel to go fight her fight before she dies.
Allister tracks down Charity and asks what she is doing in Tartarus. Charity admits she was trying to find Fiona because she’s on the hunt for the dagger that controls magic.
Back in the lair, Fiona controls harry and orders him to kill the Charmed Ones. Harry is about to kill Maggie but she uses her telepathic power to bring him back to reality. The sisters perform a spell and release Harry from the collar.
Fiona tries to attack the sisters, but they evoke the power of three and block her easily.
Fiona disappears, and the sisters and Harry realize the dagger isn’t in the lair, but out in the world ready to be found.
Back at the house, the sisters and Harry honor Tessa by giving her a funeral. Mel burns herself, and Harry heals her. They realize Harry still has his powers but he’s free of The Elders. A true free agent.
Harry explains if Fiona gets the dagger, she would be able to contain a massive amount of power. They realize the flame from the apocalypse prophecy and the dagger must bet eh same exact thing, which means witches and demons get their power from the same place. If that power is good or evil just depends on who possess it.
Allister is shown discovering the dagger.
Harry makes the sisters breakfast. Maggie is worried she hasn’t heard from Parker. Macy gets an email from the lab that says Dr. Julia died from a heart attack—Harry covered up the issue. Macy wants to use her evil sight once again to find Allister, but Harry worries it will come with a price. Macy says she hasn’t felt her demon side more at all.
At the lab, Galvin tells Macy he still wants to keep magic out of his life. Galvin tells her he’s taken a job with Doctors Without Borders and will be gone in a month.
At the bar, Mel meets up with Niko and gets her up to date. She then tells Niko they can’t hang out anymore and she needs to stop answering questions. Mel finds out Niko had nervous breakdown two years ago after a mysterious trauma that happened in her life, and she thinks there's a supernatural explanation for all of it.
Mel gives Niko a ring that will protect her from all magic. Mel freezes the room but not Niko, but instead of being scared she is extremely impressed.
Parker shows up at Allister's house. Parker declares no matter what he does, he will never evade his demon side. Allister tells him the shame Parker feels is from his human side, but there is a way out. Allister tells him to take on the Source and nothing will ever hurt him again.
Maggie gets a goodbye note from Parker. By reading the note, Macy realizes Parker must have shapeshifted into Maggie to trick Parker.
Allister begins the ceremony that allows Parker to take on the Source. He stabs Parker with the dagger.