Sonny and Arthur have been thrown together since nursery school, but the two boys couldn't be more different. Sonny is careful and studious while Arthur is a whirlwind of mess and noise.
But when Arthur is not on the school bus one day, Sonny realizes it's pretty boring without his usual seatmate. Could it be true that the two boys are good for each other, even though they are so different?
With all the humour and silliness that appeals to readers of this age, the story is cleverly told in alternating perspectives — first from Sonny's point of view, and then from Arthur's — that will get kids thinking about putting themselves in someone else's shoes.