When Grandpap teaches Charlie how to plant watermelon seeds in the spring, Charlie hopes they'll grow a "Wishing Watermelon." Grandpap has never heard of such a thing, and when he asks Charlie what he would wish for, Charlie won't tell. Through a whole summer of biking, fishing, basketball, and waiting for watermelons together, Grandpap tries to guess his grandson's harvest wish.

Lush, vivid paintings evoke the friendship, teamwork, and affection between grandfather and grandson as they share their wisdom and this special summer together.