There is that last fleeting moment right before you fall asleep when your mind empties of all thought and is replaced by nothing.
The next thing you realize is that it is the next day just one minute before the alarm is about to go off.
You wonder how that's possible, whether it is just a coincidence, something which can be explained by thorough scientific investigation, or simply some intuitive twist of the subconscious mind which is trying to trick you.
In the meantime, you have completely forgotten that last moment right before you fall asleep when your mind empties and all thought becomes nothing.
The next time you go to bed and wait long enough, you will remember it again, just a fleeting instant before the alarm is about to go off, that same cycle.
The repeating cycle that defines the fine line between what you think you are doing when awake and what you think you are dreaming when asleep.
Then you wake up and realize that all of the above was simply stuff you had been thinking within a strangely convoluted dream.