The troubles continue to mount for Barnes & Noble (BKS). It's under investigation for alleged accounting improprieties. Its founder and chairman just sold a huge chunk of stock. It's losing money hand over foot. And, most concerning of all, its free cash flow is nearing the breaking point. Could this holiday season mark the final chapter in the bookseller's storied history? In the video below, Motley Fool contributor John Maxfield explains why he thinks that it might.