Even though Leo is gone, Piper is in a surprisingly good mood, leading Paige to suspect that Leo altered Piper's memory. However, Paige's spell to restore Piper's memory accidentally causes total amnesia. Calling upon Leo for help, Phoebe and Paige discover that he is being held captive on the Island of Valhalla, a mythical place ruled by warrior-maidens. Trying to cover up his involvement in Leo's disappearance, Chris, the girls' new Whitelighter, helps them disguise themselves as Valkyries and orb onto the island. The sight of Leo causes Piper's pain to come flooding back, prompting her to stay behind on the island while everyone else escapes. The Valkryeis follow Paige and Phoebe across dimensions to San Francisco and wreak havoc on the city. Meanwhile, Phoebe discovers she has a new power and Paige takes a job as a dogwalker and is amazed when one of her dogs is transformed back into a man.

When Wyatt inadvertently brings a dragon to life, the Cleaners ,a neutral group dedicated to protecting magic from being exposed, take the child away and erase all signs and memories of his existence. Aware that they are forgetting something important but not sure of what it is, Piper, Phoebe and Paige cast a spell to return their memory but instead find themselves reliving the day Wyatt was kidnapped. Given a second chance to protect Wyatt, the sisters expose their magic in an attempt to outsmart the Cleaners. Meanwhile, Phoebe's lack of control over her new empath power causes her to start a bar room brawl; Paige's latest temp job puts her in the middle of a sexual harassment dilemma; and Leo assigns Chris a new charge.

When three evil sisters, Mitzy, Mabel and Margo, magically steal the Charmed Ones' identities and powers, Piper, Phoebe and Paige must convince Chris that they are the real Charmed Ones in order to get their lives back. Meanwhile, Piper realizes that Wyatt needs time with Leo; Phoebe and Jason sort out their feelings; Paige learns that magic will always be a part of her life; and Leo continues on his quest to find out who put him on the Island of Valhalla.

When Paige's latest temp job puts her in the middle of an ongoing feud between two magical families, the Montanas and the Callaways, she falls for Richard Montana and urges both families to consider a truce. Paige, Phoebe and Piper hold a s�ance with both families and everyone is stunned to learn that Richard's first love, Olivia Callaway, is now a ghost and has been escalating the feud to avenge her death. Paige becomes possessed by Olivia's spirit, and Phoebe and Piper must banish Olivia in order to save Paige and the two families. Meanwhile, Leo is suspicious when Chris travels to the underworld in search of a potion.

Worried that the Charmed Ones are drifting apart by putting their personal lives before their "charmed" duties, Chris tries to teach them a lesson by enlisting the help of the demon Gith , who creates an alternate reality for the sisters by tapping into their secret desires. When Piper's desire for a magic-free life with Wyatt, Paige's desire for a "real" magical place and Phoebe's desire for a successful talk show turn deadly, the sisters combine their desires to vanquish Gith. Meanwhile, Leo arranges a hearing with the Elders to strip Chris of his Whitelighter status.