A fun-filled picture book about making friends, trying new things and spreading kindness. Rainbow loves spending time with her best friend, Rain. They do everything together - just the two of them! But one day Rain does something unexpected: she invites the new girl, Star, to join their game. Rainbow is not happy - why would Rain want to play with anyone else?! Watching Rain and Star play together, Rainbow worries that everything is going to change. Has Rainbow lost her best friend forever - or could it be that friendship is even more fun with three ?.