Grab the tissues, Supernatural fans, the synopsis for the season 10 finale is out.

'Supernatural' Season 10 Spoilers: Sam's Savior Actions Prompt 'Dire Decisions' For Dean, Jensen Ackles Explains

Titled "My Brother's Keeper," the May 20 episode is primed to keep viewers on the edge of their seats as Dean (Jensen Ackles) and Sam's (Jared Padalecki) battle against the Mark of Cain comes to a head.

"Dean makes a shocking decision regarding the Mark of Cain that would change not only his life, but Sam's too," The CW teased. "Meanwhile, Crowley (Mark Sheppard) and Rowena (guest star Ruth Connell) face off and Castiel (Misha Collins) gets caught in the middle."

'Supernatural' Season 10 Spoilers: 'The Prisoner' Plot Revealed, Dean Goes On A Rampage

Ackles recently revealed that Sam's determination to save Dean - and put his life on the line in the process - will cause the elder Winchester to make some "dire decisions." Over all, not an unusual situation for the ill-fated hunters.

"The end of the season is going to be more of the same in that department; the season cliffhanger is not gonna be just a collective sigh of relief," Collins told Variety. "When the dust settles, everything is gonna be horrible for everybody."

In the meantime, The CW will air "Dark Dynasty" and "The Prisoner."

Find out more when Supernatural airs Wednesdays at 9 p.m. ET on The CW. Click the video below to see a preview for the series' next episode.