Alice and her mother meet a stranger on a Cardiff bus, and then minutes later, find her on a bench in a crowded street, panicking. Rachel is not easy to befriend, but ten-year-old Alice makes that her mission. For Alice, it's simple: the three of them need each other. But adults never see the obvious.

Alice needs an ally who knows how it feels to be excluded for her intelligence. Her mother Beth has neglected her artistic career in the struggle to support Alice. But no friendship is easy for scientist Rachel. She fights against imposing her disability, epilepsy, on Beth and Alice.

Rachel's seizures trigger painful childhood memories for Beth, and Alice is torn between loyalty to her mother and standing by Rachel. She shows insight beyond her years as she draws them together, and her loyalty to her new friend never wavers. Rachel's condition worsens, and her friends stand by her as she faces the dark.