In general, this whole story began with a valuable discovery made by some little creature. There is a detailed description of the accommodation arranged by this creature on the occasion of his birthday.
But the story becomes darker.
Now imagine another little creature, armed only with a sharp clinker and a source of light, and fearlessly entering into battle with a terrible spider-like to save the life of the little creature - the main character of the book.
A happy end, of course.
This book has even been screened.

Funny, the first this plot in the twentieth century proposed not Tolkien, but Chukovsky. "Big Brother"