Isabella Ricci has found the perfect roommate. Quiet, clean, and considerate, Lisa Fontaine is totally interested in Isabella's life. But maybe she's a little too interested... Lisa starts to dress and talk like Isabella, and instantly hits it off with all her Sweet Valley friends, especially best friend Jessica Wakefield. But Lisa crosses the line when she takes Isabella's clothes, cuts and dyes her hair just like Isabella's, and sneaks into Isabella's boyfriend Danny Wyatt's room. Suddenly Isabella is scared. Lisa seems dead set on taking her friends, her identity...maybe even her life.