A grape never forgets when someone wrongs or upsets him, turning him into a sour grape. Banana bumped into him, Lime never returned a scarf they borrowed, and Orange never called him back, so the Sour Grape holds a grudge against all of them. But the Sour Grape gets a taste of his own medicine when a friend holds a grudge against him without listening to an explanation, and he realizes that forgiveness is important.