A Twisted Story

When a dark fantasy book series was released to the public, it quickly became popular among teens. The main characters being a set of young twins, has to find their way trough a dark an twisted kingdom, were almost everyone an every thing is trying to murder them... or worse. The set of twins quickly finds people willing to help them through this twisted kingdom, but when a mysterious force finds out about the people helping the twins, it sends its worst after them. On their journey the two twins almost get killed multiple times, but of course they are the main characters so they will survive to the end, their friends aren't as lucky. The two twins end up seeing them all, get brutaly murdered by creatures sent by this mesterius force. In the end the twins escape the kingdom, and live the rest of their life in peace.
What happens when 4 fans of this book, one day, get sucked into the story. Will they survive, and use their knowledge of the book series, in their favor. Or will they meet a fate like the friends of the twins, or even a worse fate.