Mary Barton, who used to teach at a private girls' school in England, is arrested for murder when the bodies of three young children are found buried in her garden. Mary is in her fifties, eccentric, difficult, but when Matthew Hope receives a call from her former pupils, and when he sees the beautiful garden she has created, he agrees to take on her case. It is not going to be an easy one - eyewitnesses have seen her with each of the child victims - but Hope, refusing to be distracted by the fact that he's falling in love, is determined to find the truth.

196