Betsy is afraid to go out in her backyard at night, but when her friends are invited over for a camping sleepover, she is forced to face her fears. In the end, Betsy learns that there was nothing to be afraid of, and she also has learned some good lessons about the solar system. Betsy discovers that she has a loose tooth. After initially not wanting to lose her baby tooth to make way for an adult tooth, Betsy quickly changes her mind when Mrs. O'Connor announces that everyone who has lost a tooth can put their name on the "tooth chart." Now the tooth is overstaying its welcome. Betsy learns about her ever-changing body and that good nutrition is required to help her bones - and teeth - grow.