Alright here goes, but you're warned. First off this is set a year from now. Apparently Gus was part of one Pinochet's death squads back in the day and his old gang comes looking for revenge. They bust in Hank's house and immediately kill Marie. Then Junior gets his throat slit. They tie up Hank and get him to call Walt to tell him to come over. Walt knows something's up, that's what the M60 is for. He busts in Rambo style and kills everyone except one guy. The last guy is holding Holly with a gun to her head and says he will kill either Holly or Hank before Walt gets him. Walt goes to shoot, gangster dude shoots Hank, Walt kills the dude but Holly is safe. Jessie arrives at this point, Walt gives Holly to him, says something then kills himself. Jessie goes out to Walt's car and with Holly and finds the trunk is full of cash. End show.
A few other details, Walt and Skyler take all that money from the storage locker and bury it in the desert. That's the money in his trunk. Sklyer is killed in an earlier episode, I think it was the Czech gang. They also kidnap Jessie.
Might be cool to see an epilogue to find out if Jessie throws all that drug money away too. Walt originally got in the business to provide for his family after he died and Holly would be his only remaining family so the money would be for her. Jessie knows that was his original motive too.