Five-year-old Elisa has an older brother and a new baby brother, but her elderly neighbor says the middle is the best, just like the filling in a sandwich.
As the months pass during first-grade teacher Mrs. Neal's pregnancy, her class gets involved writing letters to the baby, thinking up possible names for it, and designing a baby room on the bulletin board.
Katie, an ordinary third-grader who accidentally wished on a shooting star to be anyone but herself, turns into her best friend Suzanne's baby sister, but the real trouble starts when she speaks, causing everyone to think the baby is a genius.
Eight-year-old Cassie Witting is upset when she finds out that her mother, Sarah, is expecting a baby, but writing in the journal that belonged to her brother Caleb helps her sort out her feelings and understand that Sarah will always love her.