Karla Warrior Princess New York

In book one Karla buys a book in an antique store in London, The Book of Knowledge. She starts to read it in the garden. In a blinding flash she is transported to a parallel world called Otherworld. She meets her guardian angel Blue Angel, the keeper of the book. She stays there for many years. When Karla gets old in Otherworld she decides to go back to Earth. The Book of Knowledge has been taken and sold. She ends up in an apartment in New York, she must return to where the book is kept, that is the way of Blue Angel. The new owner of the book is an American man who lives in New York, a powerful person who will stop at nothing to keep the book for himself. If she regains possession of the book will she decide to visit the parallel world in America or try to return to Otherworld in London?