"Twelve-year-old Trevor McKinney accepts his teacher's challenge to earn extra credit by coming up with a plan to change the world. Trevor's idea is simple: Do a good deed for three people and, instead of asking them to return the favor, ask them to "pay it forward" to three others who need help. He envisions a vast movement of kindness and goodwill spreading across the world and ends up changing his small California community forever."--Résumé de l'éditeur.