Property developer Charlotte Leigh's body is pulled from the Thames and, after suicide is ruled out, the main suspect is her abusive ex-husband Richard, with whom she was involved in a custody battle over their school-girl daughter Holly, but he has an alibi. Traces of Charlotte's blood are found at the flat she shared with her new man Sean and Holly. Each claim the other was pestering them sexually but Holly is charged with the murder and stands trial. However Ronnie discovers that Sean was also involved with a school-friend of Holly, which swings the case away from the accused.