Everyone knows that little sisters can be an-noy-ing! So when Ravi gets annoyed with Ruby and breaks her toy car in a rage, everyone goes to bed upset. Ravi wakes up the next morning with a bright red grumpy hat stuck fast on his head! And he can't get rid of it, no matter how hard he tries . . . . Ravi learns how to swap his grumpy hat for happy socks in this uplifting story about siblings, family life, and controlling bad moods.