The sisters are taking on the demons at Magic School but it turns out they're demons impersonating the sisters and intending to replace the Charmed Ones.
At the manor, Phoebe is helping to move out and Piper is a bit wary about it. Paige has a date that night with Henry and he's in a foul mood. Paige plans to tell him that she's a witch and Piper suggests she recruit her magical friends. At Magic School, the demon women talk to Savart, the demon attempting to coordinate them against the Slave King, who has enslaved demons. They believe they have even the Power of Three, but Savart points out they haven't shown it yet. Eventually they come up with the idea of using the magical doll house to trap the three sisters, and channel the Power of Three into themselves.
Savart teleports into the attic and steals the doll house, and Piper notices Billie has the Book of Shadows and is trying to figure out the symbol tied to her sister. Paige orbs the Book to her then sends a fairy to help her find the stuff Henry has been losing. Paige meets up with Henry later who is happy with all the lost things he's recovered. Paige then summons a Muse to help inspire Henry to get his job done. Phoebe is leaving for work when Savart knocks her out and the demon disguised as Phoebe replaces her.
Phoebe wakes up at the manor…but soon realizes she has been miniaturized and is in the dollhouse. Savart chases her back into the doll house. Piper and Paige are chatting when Fake-Phoebe arrives and tries to pass herself off despite her relative lack of current knowledge. They capture a wizard with visions of the future to try to get info on Leo, and Fake-Phoebe blows him up using the Power of Three before he can say anything. The other two female demons report in and Savart suggests one more of them slip in. Savart suggests they set up the Slave King as a suspect in Leo's problems to attract Piper, while Piper and Paige begin to wonder what's up with "Phoebe." Fake-Phoebe runs into Billie using Phoebe's room and asks her to fill her in, while Piper thinks Phoebe is focusing more on her issues then Leo.
While Paige and Henry flirt on the phone, and then Henry gets a call to report in to work so Paige contacts her leprechaun friend to give him a bit of luck. Savart then knocks her out and the demon takes her place. In the doll house, Phoebe brings Paige up to speed and they discover they can't orb out as their powers have been downsized along with them. At the manor Billie is boring Fake-Phoebe with her story of her sister and Fake-Phoebe suggest she give up. Then she links up with Fake-Paige and the two of them cover Fake-Phoebe's previous actions with Piper, then plant the idea with Piper that the Slave King is tied to Leo.
The leprechaun is at the station waiting for Paige and eventually leaves. He teleports back to the manor and Fake-Paige covers (badly). They prepare to check out the Slave King when Piper gets a brief call (a failed "Summon the Witch" spell from Phoebe and Paige, begins to wonder what's going on, and Fake-Phoebe knocks her out. Fake-Piper takes her place while Piper is imprisoned in the doll house and the other sisters bring her up to speed.
They use the spirit board to contact Billie and send her the message doll house, but she goes to the Fake sisters who tell her to get lost in no uncertain terms. The demons revert to their normal appearance and finish the potion, then head off to take on the Slave King. They confront and destroy him in his realm, and his minions go up in smoke. At the doll house, Paige eventually manages to orb a sharp stone in lace whirl Piper calls Savart over. She gives him a brief burst and knocks him onto the stone, killing him. Before they can escape the female demons return.
Piper figures out if they can get their demons to use their demonic powers, then the Sisters can draw back on the Power of Three. The Halliwells taunt them into using their demonic powers, giving Paige the chance to orb the doll house back to the manor where Billie is waiting for them. They tell her to get the Book of Shadows and use the power-switching spell, as the female demons arrive. Billie recites the spell and the demons are now trapped in the house and Piper blows it up.
Paige meets with Henry for a rooftop dinner and eventually demonstrates her magic for him. He accepts it and they kiss. Phoebe is finally getting around to moving out and Piper finally gives in and accepts it.