The executive producer told TV Guide that fans will be "tearing their hair out all summer".
"I will say we conclusively deal with Sam's amnesia [in the finale] and the fact that he doesn't remember what happened to him in Hell," he announced. "He's got this bit of drywall in his head, but it's a shabby, unstable piece of drywall."
He continued: "It's only a matter of time before the wall falls down, and in the finale, the wall falls down."
However, Kripke insisted that the events of the finale will not permanently damage the relationship between brothers Sam (Jared Padalecki) and Dean (Jensen Ackles).
"We're actually enjoying that, for the first time in a long time, the brothers are a really strong, cohesive unit," he explained. "We're going to keep them like that for the foreseeable future."
Series star Jim Beaver recently claimed that the season's final episode, written by Kripke, will "blow minds".
Supernatural returns to The CW on April 15.