Cast member Jared Padalecki (L) speaks next to writer Jeremy Carver (C) and co-star Jensen Ackles at a panel for The CW television series "Supernatural" during the Television Critics Association Cable (Photo : REUTERS/Mario Anzuoni )
The "Mark of Cain" on Dean Winchester (Jensen Ackles) is once again the storyline in "Supernatural" Season 10, episode 18 titled "Book of the Damned." In the "Supernatural" episode that aired on April 15, Charlie Bradbury (Felicia Day) returns with a book that can help get rid of the curse on Dean's arm.
Two mysterious men follow Charlie because she took the "Book of the Damned." One of the guys tells Charlie that the book belongs to his family and they will track her down to get the book back.
Castiel (Misha Collins) and the now human Metatron (Curtis Armstrong) are on a road trip to find Castiel's angel grace. At the Men of Letters bunker, Dean tells Sam (Jared Padalecki) about the Mark of Cain being a curse after his encounter with Crowley's (Mark Sheppard) witch mom, Rowena (Ruth Connell).
Charlie contacts Sam and Dean for help. The Winchester hunters tell Charlie to go to one of Bobby's nearby cabins from her location so they can meet up and deal with the book that she dug up.
Sam notices Dean is in a good mood after hearing from Charlie that the book can give them a cure for the Mark of Cain. Dean tells Sam he will go on a beach vacation if they succeed in getting rid of the curse.
Sam and Dean arrive at the cabin. Charlie tells the hunters that a nun emerged with the "Book of the Damned" after having visions of darkness.
The pages of the book were made from the slices of the nun's skin and the contents were written in her own blood. Charlie hands the book to Sam but Dean is drawn to the book with the weird drawings and symbols.
Sam tells Charlie that they need to find the cure for the Mark of Cain fast because Dean is not getting better. At the Park Crest Diner, an angel attacks Castiel and Metatron because he thinks the two corrupted Heaven.
The rogue angel gets the upper hand in fighting off Castiel. Metatron grabs the angel blade and kills the rogue angel to save Castiel's life.
Back at the cabin, Charlie shows Dean her drawing of a tattoo that she saw on one of the men who were after her. Sam tries to translate what is written in the "Book of the Damned."
The two men, who were following Charlie, show up in her last location and find out that the red-haired hunter found a way to hide the book from his tracking device. Meanwhile, Castiel and Metatron arrive at a library to retrieve Castiel's angel grace.
Metatron reveals he asked an angel to hide Castiel's grace in the library. Metatron adds he instructed the angel to leave behind clues in his favorite books.
Dean finds out that the man who is after Charlie is a member of the Stein family. Dean believes this guy is bad news but Sam argues that they have faced worse.
Dean explains the book is also bad news because he felt it call out to him and the Mark of Cain to be used for something evil. Dean wants to get rid of the book and find another way to cure the troublesome curse on his arm.
Sam insists on finding the cure on the book and dealing with the consequences later because he does not want Dean to become a demon again. Dean decides to step out to get some air and buy Charlie her snacks.
At the library, Castiel and Metatron search for the clues in finding his grace. However, Metatron tricked Castiel because he used his blood from the gunshot wound to write symbols on the books to make Castiel weak.
Aside from Castiel's grace, Metatron also had the demon tablet kept in the library. Metatron leaves the library as Castiel finds his angel grace and reunites with it.
Dean bumps into Jacob Stein at a convenience store. Dean fights off Jacob and kills one of his guys before escaping.
Dean heads back to the cabin to tell Sam and Charlie about their current problem. Dean wants Sam to burn the book even though there is a cure for the Mark of Cain.
Charlie and Dean fight off Jacob's followers while Sam burns the book. Jacob goes after Sam but the younger Winchester stabbed Jacob to death.
Sam, Castiel, Charlie and Dean reunite at the Men of Letters bunker to celebrate with pizza and beer. However, it is revealed that Sam did not really burn the "Book of the Damned" during the confrontation with Jacob Stein.
Before Jacob died, he warned Sam that his family will not stop looking for the "Book of the Damned." The ending scene shows Sam asking Rowena for help in getting rid of the Mark of Cain on Dean with the use of the book.
"Supernatural" Season 10 will return with episode 19 titled "The Werther Project" on April 22, Wednesday night at 9 p.m. ET on the CW Network.
