10-year-old Dolphin and her older half-sister, 13-year-old Star, live with their mother, Marigold, in a small council flat in London. Marigold, an avid lover of tattoos and part-time tattoo artist, has
bipolar disorder and also has a
drinking problem. Dolphin loves Marigold and thinks she is wonderful and unique, while Star is embarrassed by Marigold's tattoos and erratic behaviour. Dolphin feels like an outsider at school; she is bullied by some classmates and feels her teacher is unkind to her. She also struggles with her
dyslexia. Star appears to be more popular, and Dolphin dislikes the fact that Star has an older boyfriend. Dolphin later befriends Oliver, a shy and studious boy who spends the lunch period in the library to avoid being teased. Marigold buys tickets to see her favourite band Emerald City, with the intention of finding Micky, Star's father, who Marigold is still in love with. Both girls are surprised when she returns that night with Micky. He was unaware he had a daughter and is thrilled to meet Star, and she adores him in turn. Dolphin however dislikes him because she feels that he abandoned Marigold and neglected Star. Micky takes them all to London for the day and they do a number of fun activities and shopping. Despite it all, Dolphin feels ignored the entire day by all of them. Marigold is completely convinced they will all live together now as a family, but Micky drops them all home and returns to his place in
Brighton. In the days which follow Micky sends them presents, and Star goes to spend a weekend with him. Marigold had hoped to reconcile romantically with Micky and is upset to hear that he has a girlfriend living with him. Micky, who has no feelings for Marigold due to her mental illness, invites both Star and Dolphin to come and live with him. Dolphin, who still hates Micky, stays loyal to Marigold and refuses to abandon her but Star leaves to be with Micky. After Star leaves, Marigold has a mental breakdown and paints herself white all over using
toxic paint to hide her tattoos. Dolphin phones for an ambulance despite knowing Marigold's fear of hospitals. Later Dolphin finds out that due to her
mental illness Marigold may be in hospital for some time. With her mum ill in hospital and with nowhere else to go, Oliver encourages Dolphin to contact her father, who she knows nothing about, except that his name is also Micky and he works as a swimming instructor. Together they manage to track him down and he's pleased to meet her. Dolphin hopes he will look after her, but learns he has a wife and daughters already and decides to do things properly, getting in touch with child services so Dolphin can be in
foster care for a while. Dolphin is initially terrified of going into a foster home having heard Marigold's horror stories from her own childhood in foster homes, but she stays with a kind older woman and three babies. Her father takes her to visit Marigold, who is on medication for her bipolar disorder. The two slowly begin to develop a father-daughter relationship. Star appears at the foster home after returning to the flat to find both Marigold and Dolphin gone. Star stays in foster care with Dolphin and they argue at first, Star blaming everything on Dolphin for ruining her time with Micky and refuses to believe what Dolphin tells her. But then they reconcile and go to visit Marigold together. The story ends with Dolphin deciding that even though Marigold is in hospital and she and Star are in foster care, they are still a family. ==Adaptation==