Calypso's mum died a few years ago and her emotionally incompetent Dad can't, or won't, talk about Mum at all. Instead he throws himself into writing his book A History of the Lemon. Meanwhile the house is dusty, there's never any food in the fridge, and Calypso retreats into her own world of books and fiction.
When a new girl, Mae, arrives at school, the girls' shared love of reading and writing stories draws them together. Mae's friendship and her lively and chaotic home - where people argue and hug each other - make Calypso feel more normal than she has for a long time. But when Calypso finally plucks up the courage to invite Mae over to her own house, the girls discover the truth about her dad and his magnum opus - and Calypso's happiness starts to unravel.