Jo Shepherd, mother to Ben and Katie, lives with them and her much younger partner, triage nurse Danny. She is horrified to receive an anonymous text suggesting that "something's going on " between 11 year old Katie and Danny and, unable to identify the sender, confides in her friend Sally that Katie has been unusually withdrawn. Concerned that she is about to leave the children with Danny for a week she ultimately confronts him, resulting in him angrily walking out. Determined to hear Katie's version of events she visits her at her ex-husband Des's house to eventually discover the truth.