There’s a little boy and his best friend, a duck. They play together every day, and then one day, the little boy is nowhere to be found. The duck looks in the house, at the pond, and everywhere he can think of. He’s very sad when he can’t find the little boy, but then the little boy comes home and tells the duck he had been at school. I believe the illustrations were in a watercolor-like style. This book was read to me frequently as a child; I have few clear memories of it, and my parents don’t remember any details, including title, author, or publication year.