Complex sentence: The next two cards determine the locations of Strahd and the "Tome of Strahd", a book that details Strahd's long-ago unrequited love.
Split into simpler sentences: The next two cards determine the locations of Strahd and the "Tome of Strahd". The "Tome of Strahd" is a book that details Strahd's long-ago unrequited love.