Carrie Ryan BookFans?

I've read two of her books, "The Forest of Hands and Teeth" and "The Dead Tossed Waves." I just bought a third one today, "The Dark and Hollow Places."

I read the first two a long time ago, and I kinda forgot about some of the parts. I was wondering if you could tell me about the connection in these books. Because the girl in the first book, is the grandmother for the girl in the second book.

Please list me the important details and conflicts between the books.

I thank you very much.