It's almost Christmas. But for Ali, the season of good cheer is the anniversary of her baby's death. As she stands at her son's grave, she is poignantly aware of how dramatically her life has changed. Determined to stand on her own two feet and get through Christmas alone, Ali turns down her ex-husband's unexpected invitation to spend the holiday with him and his father, only to give in to her best friend's cajoling to share the festive season with her. The only trouble is, it means having to be nice to Sarah's awful husband, Trevor.

Sarah may be a saint for putting up with Trevor, but Ali is no such thing, and as his cranky behaviour escalates, she takes it upon herself, in an extraordinary act of daring impetuosity, to play God with her friend's incomprehensible marriage. But Ali's meddling has consequences even she could not have foreseen...