Grey is an introverted girl who often enjoys her own company. But she wishes that she could be a bit more like the other children – brave, pretty and fun. One day she is looking for interesting and beautiful stones on the beach. When she finds a grey stone speckled with many colours, she wants to show it to Red, Blue and Yellow. But they just ignore her, and Yellow runs away with her precious stone. Grey starts a search to get it back, and on the way she makes friends with many children of different colours. Finally Yellow regrets behaving badly and asks if he can play with Grey and the others.