Warning: this section contains spoilers!
The story is about a young girl called Emily, or Emerald to her dad, who lives with her mum Julie, her step-dad Frankie, her sister Vita and her brother Maxie in their grandmother Ellen's house. Their grandmother is a right snob and has always had her nose upturned to Em. Although her dad is technically only her stepdad, Em and her siblings all love him completely. Emily is quite on the large side, and is very insecure about her weight. On Christmas Day Em overhears a conversation her dad is having on the phone and realises that he is having a secret affair. Emily confronts her father, and he owns up to his cheating, and by the next morning he has left. After Emily's step-dad walks out, the rest of the family struggle to get along without him. Emily takes up swimming, where she becomes more fit, loses weight and gains confidence within herself. The children go and visit Frankie at the home of his new partner Sarah, but she is rude, selfish and obnoxious. On a visit they take to a park, Em, Vita and Maxie are astounded to find their Dad passionately kissing Sarah, in a way that he would never do to their mum. Sarah is an aspiring actress and both she and Frankie move to Scotland quite soon into their relationship. When they arrive home, they all reject their Dad's goodbyes. The children all tell their mother that Sarah and their Dad don't get on very well, and will be home soon. Their Mum is quite depressed, and dependent on Frankie for emotional support. Their grandmother does not understand how much the family all love him and would take him back if he ever returned. Em's Gran decides to take them on a holiday and gets a boyfriend herself, named Eddie. When Emily travels to London to meet her favourite author, Jenna Williams, Em sees Frankie again and begins chasing after him, but she falls and breaks her arm. She is taken to the hospital, where Frankie says he has broken up with Sarah and found a new girlfriend, Hannah. After they return home, Frankie moves back to London. The story ends on Christmas Eve just under one year after Frankie left. It is implied that he returns to the family.