The novel tells the story of private detective Roland Childs, who was investigating the strange goings on in Romania before Rise of Nightmares protagonist "Josh" fell into the mix. Throughout the adventure, Josh can collect Childs' audio tapes, piecing together the mystery of the Romanian castle and its freakish inhabitants.
Granted, story isn't exactly the game's strong suit, but then Sega is offering the graphic novel free of charge, so who's complaining? You can read the whole thing on Sega's Flickr account (starting here) or download the novel as a PDF (here). As far as we know, the graphic novel does not require a Kinect.