Lonely teenaged witch Aviva (Danielle Harris) would give anything to be the fourth Halliwell sister -- and in hopes of being accepted into the fold, Aviva attaches herself to Phoebe (Alyssa Milano). Unbeknownst to the sisters, Aviva is under the influence of duplicitous priestess Kali (Rebekah Carlton), who wants to get her claws on the Halliwell girls' magic. This, however, is but one of many problems facing the Halliwells in this episode: Phoebe and Piper (Holly Marie Combs) have become rivals for the attention of hunky handyman Leo (Brian Krause), while the relationship between Prue (Shannen Doherty) and Andy (T.W. King) has reached a crossroads. Rebecca Balding, who would appear in later episodes as Elise Rothman, is here cast in a different but no less colorful part.