This book is a sequel to Witch's Sister, Witch Water, and The Witch Herself.
Lynn and Mouse live next to an evil witch. When the witch's house burned down, the only thing that remained was a glass eye. Lynn's little brother finds the eye and starts to act evilly. Lynn notices that her family is attracted to the eye do she buries the eye, but the family is still attracted to it. When Lynn takes the eye further away from her family, she starts acting strangely just as her brother had.
When Lynn and Mouse take a walk outside, Mouse takes the eye from Lynn's pocket and throws the eye into a stream, hoping that it will cease to do evil.
Does Mouse's plan work? Read the book to find out.