There is no book called “Gad Shas.”  The quote, and the book are entirely made up.

There is a term called “Shas” used with regard to the Talmud.  It refers to the Talmud as a whole.  And, of course, Gad is one of the Twelve Tribes of Israel.  But there is no book called “Gad Shas.”

In addition, rape is not permitted in Jewish law, whether the victim is Jewish or not.