In this case, it was not considered an copyright violation. According to copyright law, only the author has the right to decide whether his work is for commercial use and only the author can decide how to use his work. If the plot of a book is similar to that of another published book but the plot does not originate from the book, then the copyright of the book does not belong to any of the creators or the authors. This is because copyright law allows authors to use their works for personal or commercial purposes without having to disclose or pay copyright fees to any third party. Therefore, if a book was written with a plot similar to another published book but did not plagiarize the book, the copyright of the book should belong to the author. He could use it for his own purposes without worrying about copyright issues.