Chuck convinces Amara to join him. He tells her his master plan and how Dean was coming to put them in a divine black hole (Adam’s plan). They fuse, well, Amara fuses with Chuck, and Chuck becomes super!Chuck. 

Meanwhile, Sam tries to keep Dean and Jack from entering the dungeon.* I mean they brawl; at one point Dean raises his gun at Sam to get him to move. Sam refuses, and tries to get through to Dean (it works!). But by then, super powered fusion!Chuck burst through the door and like the gremlin ego villain he is, he tells Castiel, the Winchesters, and Jack he’s done. Oh, and he puts Jack in a life or death situation (he doubles over in pain because he’s dying, folks). 

The episode ends with Jack dying. Does he die? Looks like the answer is not yet, if you saw the promo for next week’s episode.