Iris's baby sister Rose is a very, very fussy baby, and Grandpa takes Iris out for a special day without the baby. When Baby Rose turns out to be a fussy child and not nearly as much fun as a new doll, Iris thinks about ways to get a new sister to take her place, but with some help from her family and friends, Iris begins to appreciate her role as a big sister and learns to love Baby Rose despite all the work involved. Iris thought that having a baby sister would be just like playing with a doll. But newborn Baby Rose is a crabby cake. She fusses and cries and wails so much that Iris decides she needs a new baby sister. But with a little help from her family and her best friend, Walter, and with the passage of time, Iris discovers that being a big sister can be fun, some of the time!