Charlie calls Sam and Dean to tell them she found the Book of the Dead which could help remove the Mark of Cain. The Winchesters race to her after she tells them she's been shot by a man named Jacob Styne who says the book belongs to his family and he won't rest until he gets it back. Castiel and Metatron take a road trip to find Castiel's grace but they hit a couple road bumps along the way.
Season 10 Episode 18 of Supernatural was watched by 1,760,000 viewers, resulting in a 0.60 rating in the 18-49 demographic.
Sam Winchester is a college student bound for law school, determined to escape his family's past - unlike his older brother, Dean. Ever since they were little their father has been consumed with an obsession to find the evil forces that murdered his beloved wife, and recruited his two young sons to help them. They have grown up as hunters of the supernatural. Sam escaped this way of life after high school, and now has a happy life with his girlfriend, Jessica, and a promising future career. Dean, however, stayed behind with his father to join him in his "hunting".
After Dean arrives for Sam's help when their father goes missing, Sam must join his brother to find him. His one weekend trip to search for the missing John Winchester becomes an ongoing quest after a horrible tragedy ruins any thought of a happy life for Sam.
The two brothers, bound by tragedy and blood to their mission, travel across the country encountering terrifying and dangerous forces most believe to be nothing but superstition and folklore, such as the Lady in White, the Indian beast known as the Wendigo, Phantom Travelers who cause plane crashes, Bloody Mary, and many more.