When the coolest kid in the class drops by David's house after school, David is worried about how popular, zany Ruben Plotnick will react upon meeting unpredictable Grandma Rosie. Will he make fun of her to his classmates? Will he imitate her whispery voice? What will he do if Grandma Rosie suddenly wants to dance? To his surprise, and relief, David learns that although Ruben may be a joker, he has an instant rapport with Grandma Rosie and...