Rachel Carlson (Moore) is a successful American murder mystery author living in London with her five-year-old son, Thomas (Balawi) and her second husband, Brian (Cusick), a successful book editor who has been unable to get any of his own works published. His mother being too busy working on her latest novel to play with him, Thomas goes outside to play outside their canalside home, only to accidentally drown, devastating Rachel and putting a tailspin on her marriage and her ability to finish her latest novel.