My name is Marie Cotter and I want you to believe me. Every word of this story is true...' Seventeen-year-old Marie has had a lot to cope with in her young life. But things are getting better, especially when she gets a job working for the widower Dr Slade, looking after his four-year-old daughter, Amy. At first, her new job seems perfect. Marie loves Amy, and Amy seems to like Marie too. Then things start to change. It seems that not everyone is happy with the new arrangement. There appears to be someone else in the house - someone who is determined to come between Amy and Marie...