Sixteen-year-old Laurie finally has it made: She has a handsome boyfriend and a popular group of friends. Things start to fall apart, though, when Laurie's boyfriend swears he saw Laurie meeting another boy, even though Laurie was home sick.
Other unexplained sightings convince Laurie that she has a double, and when the mysterious figure claims to be her twin sister, Laurie investigates. Laurie discovers that she was adopted at birth, although her sister Lia was not. Instead, Lia bounced from foster home to foster home, growing more bitter--and more dangerous.
Now, although her body is confined, Lia visits Laurie through astral projection. When Laurie's friends start to get hurt, Laurie suspects Lia's trying to take over her life. Will Laurie embrace her newfound sister, or will she protect her adoptive family?