It's not terribly interesting. The cubs check out a book from the library. It's a scary book. Brother reads it to Sister. She gets scared and has trouble sleeping at night. Brother makes a scary noise and nobody sleeps well. The next day, Papa finds an old night light he had as a kid. See, lots of people are afraid of the dark. Even Papa was afraid of the dark when he was a baby. The end.
It's a good message, just not a very interesting story.
The best part: "Sister was looking at a storybook about three kittens who were arguing over which was the prettiest-- and it was a little boring." Just like this book.