Supernatural season 10
Sam will go against Dean to look for a cure for the Mark of Cain when Supernatural returns on 18 March Supernatural/Facebook

Supernatural season 10 saw Sam and Dean struggling to deal with the Mark, and their fight will continue when the show returns on 18 March.

Episode 15 is titled, The Things They Carried, where Cole pays a visit to the Winchester boys.

The official synopsis released by The CW reads as follows:

Despite Dean's (Jensen Ackles) directive to forget about looking for a cure for the Mark of Cain, Sam (Jared Padalecki) continues to do research. Dean suspects Sam is hiding something but decides to focus on a new murder case where they run into Cole (guest star Travis Aaron Wade). The three team up and learn a Khan worm is infecting men and turning them into murderers. Unfortunately, the worm makes it's way into Cole.

In the upcoming episode, Sam will continue his research for a cure without his brother's knowledge, and this might create differences between them.

Dean appears to have given up after Cain (Timothy Omundson) tells Castiel (Misha Collins) that there is no cure for the Mark and he is living proof of that.

In last week's episode titled The Executioner's Song, viewers saw Dean chopping off Cain's hands, after his shocking revelation that Dean is living his life in reverse.

While Cain starts his journey as a killer by murdering his brother Abel, Dean's final step in his journey will be killing Sam.

In the same episode, Rowena tries to pit Crowley against the Winchester boys, and by the end she is successful in her endeavour.

Mark Sheppard, who plays Crowley dished on co-star, Ruth Connell, who portrays the King of Hell's mother, Rowena.

He told Access Hollywood, "She has a fantastic character to play. It's a great character to play with and it's actually been a lot of fun watching how fast the fans have picked up on the character and enjoyed the character so much," he said.

"It's a testimony, to what she's bringing to it. I think it's a delicious character, and obviously, more to come," he teased.

Supernatural will return in a new time-slot, as the series will now air every Wednesday at 9pm starting 18 March.

Watch the new promo here: