Charlie's dad has been told that he has Alzheimer's disease, a kind of dementia. Dad has to explain what this means to help prepare Charlie for what might happen. To help themselves deal with this, the family think of the Alzheimer's as an unwanted guest in their home, and they call him Al, short for Alzheimer's. Dad's dementia means that he might say or do strange things, but thinking of Al as a person means the family can blame him rather than Dad. They even laugh at some of the things Al makes Dad do. The family know that Al won't go away, and they pull together to support one another as Dad's condition gets worse. They know that Dad can't always help what he says or does, but whatever happens, even when he can no longer tell them, he still loves them from the ends of the earth and back. This is Charlie's story.