Mr. and Mrs. Oliver are delighted to find a newborn baby on their doorstep one morning, but must learn to adapt when they discover that he is not like other babies.
First grader Russell Michaels grows more than an inch taller, becoming big enough to wear his red slicker and big enough to deal with family and school challenges.
Five-year-old Russell goes to nursery school and has various adventures which show he is growing up, but sometimes he wishes he could still stay home like his baby sister.
Baby Bear discovers that he is now old enough to dress himself, eat breakfast by himself, and give himself a bath, but perhaps most wonderful of all he will never be too big for a goodnight kiss.