Bad Seed focuses on the seemingly perfect little girl, Rhoda Penmark, who can charm her way into getting just about anything she wants. Anything, except a highly coveted penmanship medal that her teacher has awarded to Claude Daigle, one of Rhoda's classmates. During a school outing near the shore, Claude goes missing, and it is soon discovered that he has drowned near a pier. Rhoda's mother, Christine, begins to suspect that Rhoda had something to do with the boy's death when she finds Claude's penmanship medal hidden in Rhoda's room. Gradually, Christine comes to believe that Rhoda was behind other sudden deaths surrounding the family.

The show begs the age-old question: Are we born evil, or is evil thrust upon us?