Deputy Assistant Commissioner Charlie Hillian is killed on the night of his retirement party. Hillian was at one time a senior officer in Oxford and was in fact Morse's boss. He was also writing a book about his most memorable cases, including one about the unsolved death of an 8-year-old girl some 18 years ago. The suspect in that case, Frederick Redpath, was at Hillian's house the day he died and that chapter from the manuscript is missing. There are other suspects however, including Hillian's ghost writer who will now receive all of the book's royalties; a handyman who was working on the property; and Redpath's daughter, who knew the little girl who was killed all those years before. Morse es into nflict with with a lleague DCI Dawson, who was one of Hillian's protégés, as they again look into the little girl's death.