The sisters are at P3, talking, when Chris passes. They invite him to join them, but he declines, claiming research for the next demon on his list. Chris walks into a back room, only to find Bianca, a Phoenix, waiting for him there. She tries to steal his powers, but Piper walks in shortly after and blasts Bianca. Chris claims not to know her, though he'd said her name in obvious surprise when he saw her. Bianca reforms outside of P3, unbeknownst to Piper, who believes the vanquish worked.
Chris hedges the sisters' questions as they try to identify her in the Book of Shadows, again claiming not to know Bianca. Leo doesn't believe him. He claims to be unhurt, but in fact has a large wound on his chest.
Chris holds an engagement ring and remembers the future that he came from. In a flashforward, Chris gives Bianca a ring and asks her to marry him. Some kind of flying probe points at them, but Chris blasts it. Chris makes his plan to go back in time.
Leo has found the entry for the Phoenix coven in the Book of Shadows. Paige scries for Bianca, and she and Piper find only a little girl with a tattoo on her left arm. The girl's mother hurls energy balls and Piper blasts her. Looking for the girl, they see the mother reform.
Chris meets with Bianca. She tells him he'll die if he doesn't go back. She tries again to steal his powers as he orbs away. Chris orbs into the manor and says only "Bianca" before collapsing. Leo finds his chest wound, but cannot heal him. Phoebe gets an empathic read on Chris and realizes that Chris loves Bianca. She finds the engagement ring and the sisters use it to scry for Bianca.
A flashforward finds a guided tour of the manor, now called the Halliwell Memorial Museum. Chris and Bianca slip in unnoticed as the tour guide shows footage of the Charmed Ones' reconstitution ("Charmed Again"). Away from the tour, a demon shimmers in behind them, but Bianca vanquishes it with an athame. They hide in the basement and plan to reach the Book of Shadows.
In the present, Bianca rummages through her mother's house when the mother shimmers in. Bianca shows the tattoo and demands to know where the Grimoire is. The mother shimmers the Grimoire in and Bianca quickly reads a spell. The Charmed Ones suddenly lose their inhibitions, worrying Leo.
In the future, Chris and Bianca have reached the attic. Chris is to pass himself off as the Charmed Ones' Whitelighter. There is only a holographic image of the Book of Shadows, but Chris plans to summon the real one.
With the sisters scattered, Bianca attacks Leo and shimmers away with Chris.
Piper is getting horizontal with Greg on top of a fire truck, when Leo orbs in. Piper, alarmed, freezes Greg and Leo throws a potion, freeing Piper of the spell. Paige is with Richard, when Leo and Piper orb in and Leo throws another potion.
Bianca has taken Chris' powers, and is preparing to return to the future. She tells Chris that he will keep facing more assassins if he doesn't go back.
In the future, Bianca draws a large triquetra on the wall of the attic. Bianca gives Chris her engagement ring as a keepsake. Chris summons the real Book of Shadows with a spell and reads another spell to open a portal in the triquetra. A demon shimmers in after them, but Bianca fights him off.
In the present, Bianca prepares to open a time portal, as the Charmed Ones orb in. Bianca holds a knife to Piper's throat, but Chris convinces her not to kill Piper. He steps through the portal with Bianca and is met by several bodyguards and a long-haired man -- the full-grown Wyatt.
The sisters plan to save Chris. Chris had pointed out a squeaky board in the attic, and the sisters plan to use it to send Chris his powers. They slip a note under the board with a spell.
In the future, Chris and Bianca confront Wyatt, who has become an evil witch-king. Wyatt tells Chris he will spare his life if he promises never to cross him again; Chris won't make that promise. Wyatt raises a hand and blows Chris across the attic. Bianca restrains Wyatt while Chris looks for the note. He reads the spell and gets his powers back. He and Bianca fight Wyatt off, but Bianca is fatally injured. Chris reads a spell from the Book of Shadows and jumps back to the present. Chris tells the sisters he came from the future "to save Wyatt"; from what, he won't say.
Later that night, Piper, Phoebe and Paige have a meeting. Piper tells them to move out and join their boyfriends.