Things that could happen next episode:
- The white walkers attack and destroy Castle Black, and possibly Sam, Gilly or the baby will die
- Arya fights Meryn Trant and kills him, but a lot of people will get caught up in it and die. Arya could be injured as well.
- Any one of Daenerys's team could die, except maybe Tyrion. They would die trying to defend her from the Sons of the Harpy.
- One of the dragons could possibly get out of control - and maybe Daenerys would have to slay them.
- Jorah gets overcome by greyscale and will attack Daenerys
- Like Riverwide said, Davos probably might try to kill Melisandre, but he would fail and end up exiled or executed.
- Shireen's mother would also try to kill Mel or Stannis and she would be killed.
- The trial at King's Landing goes horribly wrong, and Cersei, Maergery or Loras will be executed.
- The religious order will kill Tommen and Myrcella in an accident
- Sansa will kill Ramsey, or Theon will finally get revenge but be killed in the process. I don't think Sansa will die.
- Brienne will storm Winterfell, but will be unsuccessful and may die.
Basically someone will definitely die