Charmed (1998)

S8E21 Kill Billie: Vol. 2

Title: Kill Billie: Vol. 2 Plot: As the Charmed Ones evade Billie and Christy, they become trapped in the Underworld. Leo visits Piper, providing her with demonic endorsement, while Coop embarks on a quest to locate Phoebe. In a bid to eliminate the Charmed Ones, Billie and Christy decide to summon the Hollow, prompting the Charmed Ones to counter with their own invocation of the powerful entity.