Franklin the turtle anxiously awaits the arrival of spring as he looks forward to the birth of his new baby sister and the prospect of becoming a big brother.
His sister D.W. convinces Arthur to have a garage sale after his mother tells him to get rid of the junk in his room, but things do not work out exactly as he had planned.
Nine-year-old Nathan helps welcome his baby sister, who has Down's syndrome, into the family and eagerly anticipates the day when she will be able to ride his tricycle.