A medical professional has a natural, anatomically-correct medical dummy, with muscular tissues as well as organs noticeable through its clear skin, named Pin (after Pinocchio). Via ventriloquism, Pin describes bodily functions in a way children can relate to. When the over-strict medical professional and his partner are killed in an auto accident, his kid (Leon) transfers his alter-ego right into Pin, whom he always thought lived. He begins using Pin as an excuse to over-protect his sister (Ursula) from admirers as well as deflect unwanted invasions, even for devoting murder.