Teenage years can be complicated, even when you haven't been abandoned by your mother at age ten. It is the 1980s and teenage Gemma lives with her well-meaning father, Nathaniel, goes to 'art therapy' once a week and tries to come to terms with growing up motherless. She collects facts about her long lost mother, Angie (height, weight, eye-colour, mint lip-gloss) and develops a rare syndrome she calls PMMSM, People-Make-Me-Stupid-Mad. Then comes the strange, almost unthinkable news: Angie is back, attending church in a nearby town. She is ready to return to motherhood, and to prove it, she has adopted a Korean infant. Then an invitation: would Gemma like to stay with a family in Angie's community over the summer? Gemma, who has never had a friend in her life, suddenly finds herself living in a house full of God-fearing teenagers, and every Sunday, facing the prospect of maybe, just maybe, seeing a mother she is pretty sure she hates.