As opening arguments were heard Monday in the DaVinci Code copyright infringement case in London, the web of plots and subplots had become so tangled as to nearly approximate the book at the center of the storm. But while the details may be confusing, what is at stake in the case is abundantly clear. DaVinci is the greatest money-making machine the publishing world has at the moment, and if it is found to have been illegally cribbed from the work of others, the whole synergistic apparatus could come crashing down.