Once upon a time there was a magical man known only as "The Doctor" who traveled all around time and space in a magic machine called the TARDIS that looked like a police box on the outside, but was endlessly bigger on the inside. One night, when he was flying his magic box, he crashed into the backyard of a little girl named Amelia. Amelia had a large crack in her wall, and she knew there was something wrong with it. It scared her. She heard whispers through it. So she went out into her backyard and asked the magical man if he could help her with the crack in her wall.
The Doctor opened up the crack in her wall, and found something terrifying on the other side. He found a prison, where a prisoner known as Prisoner Zero had gotten out. Prisoner Zero could disguise himself as anyone, and he had escaped through Amelia's wall. But Prisoner Zero's jailers would not let him get away. They said that if they didn't find Prisoner Zero, they would blow up the whole world to stop him.
The Doctor stopped Prisoner Zero, and returned him to his captors, thus saving the Earth. But not before Prisoner Zero gave him a terrifying warning: "The Universe is cracked. The Pandorica will open. Silence will fall."
When Amelia was an adult, the Doctor took her and her fiance with him on his adventures. But someone called the Silence was chasing after him. The Silence was an evil cult that believed that it was very important to kill the Doctor before he was someday forced to answer the question that must never be answered, a question that they believed was the oldest question of all time, hidden in plain sight. They believed it was very important that the answer never be spoken.
The Silence developed a plan to blow up the Doctor's TARDIS and kill him, but they didn't realize that they could blow up the whole of time and space if they did that. The Doctor's enemies, fearing that the TARDIS would destroy the Universe, locked the Doctor in a mythical prison called the Pandorica so that he couldn't pilot the TARDIS. But the Doctor wasn't piloting the TARDIS, his wife, River Song, was, and so the Silence were able to blow up the TARDIS, thus destroying the whole Universe.
But before the Universe could be destroyed, the Doctor flew the Pandorica and himself into the explosion of his TARDIS, which reset the whole universe and brought it back. But it erased him from time in the process. He had never existed, and nobody could remember him. Except Amelia. She knew something was missing, but she didn't know what. On the day of her wedding, she realized who was missing, and tried very hard to remember him. She wished and wished so hard, and finally, the Doctor showed up, all thanks to Amelie's memory.
The Silence didn't give up, though. When Amelia and her husband had a baby girl, the Silence stole her and raised her to be an assassin. Their assassin, River, however, fell in love with the Doctor, and couldn't bring herself to kill the Doctor. So instead, River helped the Doctor to fake his death, so that the Silence would stop trying to kill him. So the Doctor ran off to hide from the Silence, but he still had to worry about the prophesy that the Silence believed: "On the fields of Trenzalore, at the fall of the eleventh, where no man can refuse to answer or speak falsely, a question will be asked that must never be asked: The first question, the oldest question in the Universe, hidden in plain sight: Doctor who?"
The Doctor's name must never be said...
If you write it a certain way, Moffat's entire era reads like a fairy tale or an ancient legend. There's a very good reason why Moffat's style has been referred to as the "dark fairy tale" style.
In Moffat's first episode, "The Eleventh Hour," Prisoner Zero gave us the prophesy that would fuel the overarching plot of the next three seasons. "The Universe is cracked. The Pandorica will open. Silence will fall." Barring any other twist that raises another question to be answered next season, what we're likely to be looking at tomorrow is the culmination of everything that Moffat has written since he took over the show. Seasons 16 and 23 of the classic series had season-long arcs. Season 3 of the classic series featured one story that was made up of 12 half-hour long episodes. Seasons 1-4 of the current series had very subtle season long arcs. Never before has Doctor Who told a story steeped in deep mystery that lasted 3 years. This is quite an accomplishment that finally comes to a head tomorrow night. We finally understand why the question must never be answered.
Or perhaps we'll learn nothing at all. Still, it promises to be a hugely momentous episode. I can't wait!