Supernatural finale - Jensen Ackles by Sergei Bachlakov/The CW
's Dean (
) is down to his final 24 hours! It's been a year since he made a deal with demons to save the life of his brother, Sam ( Jared Padalecki
), by sacrificing his own - and his debt is due. "The boys race like hell to save him," says exec producer Eric Kripke
. Their last two attempts failed miserably, but now, Kripke reveals, "they know who holds the deal and how to kill them." But don't expect salvation for the Winchester brothers. "We leave them in a pretty suspenseful place," Kripke says. "I hope it will drive everybody crazy until we're back in the fall."