Faith still refuses BUffy's help, instead choosing to go and work for the Mayor.
When the scoobies break into City Hall to steal the Box of Gavrok, Faith captures Willow. When Faith discovers Will has read alot of the Books of Ascension she starts beating on her before the Mayor intervines. They exchange Willow for the Box of Gavrok, and during the exchange, Faith appears to regret her decision.
Buffy goes to Faith's apartment where they end up in another fight, resulting in Buffy stabbing Faith with her own knife. She falls from the roof and ends up in the hospital in a coma.

Faith remains in the coma for 8 months, no-one expects her to ever wake up, but when she does, she wants revenge. She seeks out Buffy in the only home she's known her living in. She finds Joyce and discovers that Buffy probably hasnt been home much recently. Buffy finds out Faith is awake and out of the hospital and rushes home to save her mum.
Faith and Buffy fight and Faith seems to let Buffy beat her down before using a Draconian Katra to switch bodies with her. Faith assumes Buffy's role, meeting with the scoobies, slaying, partying, even going as far as to sleep with Riley.
With everyone thinking she is Buffy, she is introduced to Tara and immediately realises she and Willow are more than just friends and makes fun of them and Tara's stutter, prompting Tara to believe that she isn't actually Buffy.

When Faith is at the airport preparing to leave Sunnydale, she sees a news report on the tv about churchgoers trapped in the church by what appears to be vampires. Thanks to the love and friendship shown to her as Buffy, she has an attack of conscience and goes to help.
After slaying the vampires, Buffy arrives and the pair fight again. Buffy has a 'home conjured' version of the katra that Faith used to switch them and manages to switch them back to their relevant bodies.
Back in her own body, Faith takes off and is last seen in the back of a freight train heading off to who knows where......