Rebecca Dessertine & David Reed 
War of the Sons [EPUB ebook] 

A Supernatural novel that reveals a previously unseen adventure for the Winchester brothers, from the hit TV series! Twenty-three years ago, Sam and Dean Winchester lost their mother to a demonic supernatural force. Following the tragedy, their father taught the boys everything about the paranormal evil that lives in the dark corners of America… and how to kill it. On the hunt for Lucifer, the boys find themselves in a small town in South Dakota where they meet Don – an angel with a proposition… How far will the boys go to uncover the secret Satan never wanted them to find out?